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/ls1043aqds_tfa_SECURE_BOOT_defconfig b/configs/ls1043aqds_tfa_SECURE_BOOT_defconfig
index 40fbddd..9035594 100644
--- a/configs/ls1043aqds_tfa_SECURE_BOOT_defconfig
+++ b/configs/ls1043aqds_tfa_SECURE_BOOT_defconfig
@@ -36,6 +36,7 @@
 # CONFIG_USE_BOOTCOMMAND is not set
 CONFIG_MISC_INIT_R=y
 CONFIG_SYS_MAXARGS=64
+CONFIG_SYS_PBSIZE=532
 CONFIG_CMD_BOOTZ=y
 CONFIG_CMD_IMLS=y
 CONFIG_CMD_GREPENV=y