Kconfig: Move config IDENT_STRING to Kconfig

Move the config IDENT_STRING to Kconfig and migrate all boards

[sivadur: Migrate zynq boards]
Signed-off-by: Siva Durga Prasad Paladugu <sivadur@xilinx.com>
[trini: Update configs, add some default to sunxi Kconfig]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/spear310_usbtty_defconfig b/configs/spear310_usbtty_defconfig
index a690e3a..f35d363 100644
--- a/configs/spear310_usbtty_defconfig
+++ b/configs/spear310_usbtty_defconfig
@@ -1,5 +1,6 @@
 CONFIG_ARM=y
 CONFIG_TARGET_SPEAR310=y
+CONFIG_IDENT_STRING="-SPEAr"
 CONFIG_SYS_EXTRA_OPTIONS="SPEAR310,USBTTY"
 CONFIG_BOOTDELAY=-1
 CONFIG_CMD_I2C=y