Convert CONFIG_SYS_LOAD_ADDR to Kconfig

Now that we have consistent usage, migrate this symbol to Kconfig.

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Rick Chen <rick@andestech.com>
diff --git a/configs/octeon_ebb7304_defconfig b/configs/octeon_ebb7304_defconfig
index a2b8c3c..97364f0 100644
--- a/configs/octeon_ebb7304_defconfig
+++ b/configs/octeon_ebb7304_defconfig
@@ -12,6 +12,7 @@
 CONFIG_MIPS_RELOCATION_TABLE_SIZE=0xc000
 CONFIG_DEBUG_UART=y
 CONFIG_OF_BOARD_FIXUP=y
+CONFIG_SYS_LOAD_ADDR=0xffffffff80100000
 CONFIG_SYS_CONSOLE_INFO_QUIET=y
 CONFIG_BOARD_LATE_INIT=y
 CONFIG_HUSH_PARSER=y