Convert CONFIG_SYS_BARGSIZE to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_BARGSIZE

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/gazerbeam_defconfig b/configs/gazerbeam_defconfig
index 2f3b29e..c48541a 100644
--- a/configs/gazerbeam_defconfig
+++ b/configs/gazerbeam_defconfig
@@ -112,6 +112,7 @@
 CONFIG_CMD_IOLOOP=y
 CONFIG_SYS_MEMTEST_START=0x00001000
 CONFIG_SYS_MEMTEST_END=0x07e00000
+CONFIG_SYS_BARGSIZE=1024
 CONFIG_FIT=y
 CONFIG_FIT_SIGNATURE=y
 CONFIG_FIT_VERBOSE=y