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/conga-qeval20-qa3-e3845-internal-uart_defconfig b/configs/conga-qeval20-qa3-e3845-internal-uart_defconfig
index 1c5efec..c41b831 100644
--- a/configs/conga-qeval20-qa3-e3845-internal-uart_defconfig
+++ b/configs/conga-qeval20-qa3-e3845-internal-uart_defconfig
@@ -32,6 +32,7 @@
 CONFIG_DISPLAY_BOARDINFO_LATE=y
 CONFIG_LAST_STAGE_INIT=y
 CONFIG_HUSH_PARSER=y
+CONFIG_SYS_PBSIZE=532
 CONFIG_CMD_CPU=y
 CONFIG_CMD_GPIO=y
 CONFIG_CMD_I2C=y