davinci: kconfig: move board select menu and common settings

Becuase the board select menu in arch/arm/Kconfig is too big,
move the Davinci board select menu to davinci/Kconfig.

Move also common settings (CONFIG_SYS_CPU="arm926ejs" and
CONFIG_SYS_SOC="davinci").

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Reviewed-by: Tom Rini <trini@ti.com>
Cc: Heiko Schocher <hs@denx.de>
Cc: Sandeep Paulraj <s-paulraj@ti.com>
diff --git a/configs/da850evm_defconfig b/configs/da850evm_defconfig
index 7517e92..afdce5e 100644
--- a/configs/da850evm_defconfig
+++ b/configs/da850evm_defconfig
@@ -1,4 +1,5 @@
 CONFIG_SPL=y
 CONFIG_SYS_EXTRA_OPTIONS="MAC_ADDR_IN_SPIFLASH"
 +S:CONFIG_ARM=y
++S:CONFIG_ARCH_DAVINCI=y
 +S:CONFIG_TARGET_DA850EVM=y