Convert CONFIG_SYS_PBSIZE to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_PBSIZE

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/meerkat96_defconfig b/configs/meerkat96_defconfig
index 31e436d..4fdcdaf 100644
--- a/configs/meerkat96_defconfig
+++ b/configs/meerkat96_defconfig
@@ -16,6 +16,7 @@
 CONFIG_SYS_MEMTEST_END=0xa0000000
 CONFIG_HUSH_PARSER=y
 CONFIG_SYS_MAXARGS=32
+CONFIG_SYS_PBSIZE=532
 # CONFIG_CMD_BOOTD is not set
 CONFIG_CMD_BOOTZ=y
 # CONFIG_CMD_IMI is not set