dra7xx_evm: Enabled UART-boot mode and add dra7xx_evm_uart3 build

UART booting is supported on this SoC, but via UART3 rather than UART1.
Because of this we must change the board to use UART3 for all console
access (only one UART is exposed on this board and a slight HW mod is
required to switch UARTs).

Signed-off-by: Minal Shah <minal.shah@ti.com>
[trini: Make apply to mainline, reword commit]
Signed-off-by: Tom Rini <trini@ti.com>
diff --git a/boards.cfg b/boards.cfg
index 0d4f2e0..3a56eab 100644
--- a/boards.cfg
+++ b/boards.cfg
@@ -334,7 +334,8 @@
 Active  arm         armv7          omap3       timll           devkit8000          devkit8000                           -                                                                                                                                 Thomas Weber <weber@corscience.de>
 Active  arm         armv7          omap4       ti              panda               omap4_panda                          -                                                                                                                                 Sricharan R <r.sricharan@ti.com>
 Active  arm         armv7          omap4       ti              sdp4430             omap4_sdp4430                        -                                                                                                                                 Sricharan R <r.sricharan@ti.com>
-Active  arm         armv7          omap5       ti              dra7xx              dra7xx_evm                           -                                                                                                                                 Lokesh Vutla <lokeshvutla@ti.com>
+Active  arm         armv7          omap5       ti              dra7xx              dra7xx_evm                           dra7xx_evm:CONS_INDEX=1                                                                                                           Lokesh Vutla <lokeshvutla@ti.com>
+Active  arm         armv7          omap5       ti              dra7xx              dra7xx_evm_uart3                     dra7xx_evm:CONS_INDEX=3,SPL_YMODEM_SUPPORT                                                                                        Lokesh Vutla <lokeshvutla@ti.com>
 Active  arm         armv7          omap5       ti              omap5_uevm          omap5_uevm                           -                                                                                                                                 -
 Active  arm         armv7          rmobile     atmark-techno   armadillo-800eva    armadillo-800eva                     -                                                                                                                                 Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
 Active  arm         armv7          rmobile     kmc             kzm9g               kzm9g                                -                                                                                                                                 Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>:Tetsuyuki Kobayashi <koba@kmckk.co.jp>