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/odroid_defconfig b/configs/odroid_defconfig
index f2a8cd4..a4013a6 100644
--- a/configs/odroid_defconfig
+++ b/configs/odroid_defconfig
@@ -27,6 +27,7 @@
 CONFIG_BOARD_LATE_INIT=y
 CONFIG_MISC_INIT_R=y
 CONFIG_SYS_PROMPT="Odroid # "
+CONFIG_SYS_PBSIZE=1024
 # CONFIG_CMD_XIMG is not set
 CONFIG_CMD_THOR_DOWNLOAD=y
 CONFIG_CMD_DFU=y