scripts/checkpatch.pl: Upgrade IS_ENABLED_CONFIG to error for U-Boot

A problem we have today is that some instances of IS_ENABLED(FOO) have
crept in to the code. This is in turn because with checkpatch.pl this is
only a warning and not an error, so they were overlooked. And looking
deeper, in the Linux kernel this pattern is allowed because
IS_ENABLED(DEFINED_FLAG) is allowed if discouraged and a quick skim of
the instances I saw in the current kernel follow this pattern. In U-Boot
however, this is not allowed, so bump to an error.

Signed-off-by: Tom Rini <[email protected]>

Author: trini

scripts/checkpatch.pl

@@ -7205,8 +7205,8 @@ sub process {
 
 # check for IS_ENABLED() without CONFIG_<FOO> ($rawline for comments too)
 		if ($rawline =~ /\bIS_ENABLED\s*\(\s*(\w+)\s*\)/ && $1 !~ /^${CONFIG_}/) {
-			WARN("IS_ENABLED_CONFIG",
-			     "IS_ENABLED($1) is normally used as IS_ENABLED(${CONFIG_}$1)\n" . $herecurr);
+			ERROR("IS_ENABLED_CONFIG",
+			     "IS_ENABLED($1) must be used as IS_ENABLED(${CONFIG_}$1)\n" . $herecurr);
 		}
 
 # check for #if defined CONFIG_<FOO> || defined CONFIG_<FOO>_MODULE