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/iconnect_defconfig b/configs/iconnect_defconfig
index 57d647f..879f3d3 100644
--- a/configs/iconnect_defconfig
+++ b/configs/iconnect_defconfig
@@ -23,6 +23,7 @@
 CONFIG_HUSH_PARSER=y
 CONFIG_SYS_PROMPT="iConnect> "
 CONFIG_SYS_MAXARGS=32
+CONFIG_SYS_PBSIZE=1051
 # CONFIG_CMD_FLASH is not set
 CONFIG_CMD_NAND=y
 CONFIG_CMD_PCI=y