Kconfig: Rename SPL_MD5_SUPPORT to SPL_MD5

Drop the _SUPPORT suffix so we can use CONFIG_IS_ENABLED() with this
option.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
diff --git a/common/spl/Kconfig b/common/spl/Kconfig
index 896526a..2df3e5d 100644
--- a/common/spl/Kconfig
+++ b/common/spl/Kconfig
@@ -417,7 +417,7 @@
 	  for detected accidental image corruption. For secure applications you
 	  should consider SHA1 or SHA256.
 
-config SPL_MD5_SUPPORT
+config SPL_MD5
 	bool "Support MD5"
 	depends on SPL_FIT
 	help