Convert CONFIG_BMP_16BPP to Kconfig

This converts the following to Kconfig:
   CONFIG_BMP_16BPP

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/am335x_guardian_defconfig b/configs/am335x_guardian_defconfig
index ea4032f..9d9d628 100644
--- a/configs/am335x_guardian_defconfig
+++ b/configs/am335x_guardian_defconfig
@@ -122,6 +122,7 @@
 CONFIG_USB_ETHER=y
 CONFIG_SYS_WHITE_ON_BLACK=y
 CONFIG_AM335X_LCD=y
+CONFIG_BMP_16BPP=y
 CONFIG_SPL_WDT=y
 # CONFIG_SPL_USE_TINY_PRINTF is not set
 CONFIG_SPL_OF_LIBFDT=y