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/apalis-tk1_defconfig b/configs/apalis-tk1_defconfig
index e017b7e..4d8ebc4 100644
--- a/configs/apalis-tk1_defconfig
+++ b/configs/apalis-tk1_defconfig
@@ -23,6 +23,7 @@
 CONFIG_ARCH_MISC_INIT=y
 CONFIG_SYS_PROMPT="Apalis TK1 # "
 CONFIG_SYS_MAXARGS=32
+CONFIG_SYS_PBSIZE=1054
 # CONFIG_CMD_IMI is not set
 CONFIG_CMD_GPIO=y
 CONFIG_CMD_I2C=y