ti: keystone2: Move CONFIG_ISW_ENTRY_ADDR to a common place

The ISW_ENTRY_ADDR Kconfig option under mach-omap2 isn't a SoC specific
notion but rather "where is our previous stage loaded in memory?"
option.  Make use of this on ARCH_KEYSTONE rather than SPL_TEXT_BASE for
our HS builds that are not using SPL anyhow.

Cc: Vitaly Andrianov <vitalya@ti.com>
Cc: Andrew F. Davis <afd@ti.com>
Cc: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Lokesh Vutla <lokeshvutla@ti.com?
diff --git a/configs/k2g_hs_evm_defconfig b/configs/k2g_hs_evm_defconfig
index 990c7f6..9c7e3ca 100644
--- a/configs/k2g_hs_evm_defconfig
+++ b/configs/k2g_hs_evm_defconfig
@@ -1,6 +1,7 @@
 CONFIG_ARM=y
 CONFIG_ARCH_KEYSTONE=y
 CONFIG_TI_SECURE_DEVICE=y
+CONFIG_ISW_ENTRY_ADDR=0xC0A0000
 CONFIG_SYS_TEXT_BASE=0xC000060
 CONFIG_TI_COMMON_CMD_OPTIONS=y
 CONFIG_TARGET_K2G_EVM=y