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/am335x_shc_ict_defconfig b/configs/am335x_shc_ict_defconfig
index a8111e9..b0146a3 100644
--- a/configs/am335x_shc_ict_defconfig
+++ b/configs/am335x_shc_ict_defconfig
@@ -40,6 +40,7 @@
 # CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC is not set
 CONFIG_SYS_PROMPT="U-Boot# "
 CONFIG_SYS_MAXARGS=64
+CONFIG_SYS_PBSIZE=1049
 CONFIG_CMD_GPIO=y
 CONFIG_CMD_GPT=y
 CONFIG_CMD_MMC=y