spl: Convert nor to spl_load

This converts the nor load method to use spl_load. As a result it also
adds support for LOAD_FIT_FULL. Since this is the last caller of
spl_load_legacy_img, it has been removed.

We can't load FITs with external data with SPL_LOAD_FIT_FULL, so disable the
test in that case. No boards enable SPL_NOR_SUPPORT and SPL_LOAD_FIT_FULL, so
this is not a regression.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/include/spl_load.h b/include/spl_load.h
index 4777f84..b48f803 100644
--- a/include/spl_load.h
+++ b/include/spl_load.h
@@ -100,6 +100,7 @@
 	IS_ENABLED(CONFIG_SPL_SYS_MMCSD_RAW_MODE) + \
 	(IS_ENABLED(CONFIG_SPL_NAND_SUPPORT) && !IS_ENABLED(CONFIG_SPL_UBI)) + \
 	IS_ENABLED(CONFIG_SPL_NET) + \
+	IS_ENABLED(CONFIG_SPL_NOR_SUPPORT) + \
 	0
 
 #if SPL_LOAD_USERS > 1