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/netspace_max_v2_defconfig b/configs/netspace_max_v2_defconfig
index 4f85aa7..802c5ea 100644
--- a/configs/netspace_max_v2_defconfig
+++ b/configs/netspace_max_v2_defconfig
@@ -29,6 +29,7 @@
 CONFIG_HUSH_PARSER=y
 CONFIG_SYS_PROMPT="ns2> "
 CONFIG_SYS_MAXARGS=32
+CONFIG_SYS_PBSIZE=1046
 CONFIG_CMD_EEPROM=y
 CONFIG_SYS_EEPROM_PAGE_WRITE_BITS=4
 CONFIG_CMD_I2C=y