configs: Migrate CONFIG_NR_DRAM_BANKS

We have the following cases:
- CONFIG_NR_DRAM_BANKS was defined, migrate normally
- CONFIG_NR_DRAM_BANKS_MAX was defined and then used for
  CONFIG_NR_DRAM_BANKS after a check, just migrate it over now.
- CONFIG_NR_DRAM_BANKS was very oddly defined on p2771-0000-* (to 1024 +
  2), set this to 8.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/vexpress_ca15_tc2_defconfig b/configs/vexpress_ca15_tc2_defconfig
index 9aba467..adf2ede 100644
--- a/configs/vexpress_ca15_tc2_defconfig
+++ b/configs/vexpress_ca15_tc2_defconfig
@@ -2,6 +2,7 @@
 CONFIG_TARGET_VEXPRESS_CA15_TC2=y
 CONFIG_SYS_TEXT_BASE=0x80800000
 CONFIG_DISTRO_DEFAULTS=y
+CONFIG_NR_DRAM_BANKS=2
 CONFIG_OF_BOARD_SETUP=y
 CONFIG_BOOTCOMMAND="run distro_bootcmd; run bootflash"
 # CONFIG_DISPLAY_CPUINFO is not set