Makefile: avoid false positive -Wmaybe-uninitialized

When compiling with -Og gcc reports false positive -Wmaybe-uninitialized as
reported in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78394.

Silence these warnings when building with CONFIG_CC_OPTIMIZE_FOR_DEBUG.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/Makefile b/Makefile
index df0d64b..1a66f69 100644
--- a/Makefile
+++ b/Makefile
@@ -676,6 +676,9 @@
 ifdef CONFIG_CC_OPTIMIZE_FOR_DEBUG
 KBUILD_HOSTCFLAGS   := -Wall -Wstrict-prototypes -Og -g -fomit-frame-pointer \
 		$(HOST_LFS_CFLAGS) $(HOSTCFLAGS)
+# Avoid false positives -Wmaybe-uninitialized
+# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78394
+KBUILD_HOSTCFLAGS   += -Wno-maybe-uninitialized
 KBUILD_HOSTCXXFLAGS := -Og -g $(HOST_LFS_CFLAGS) $(HOSTCXXFLAGS)
 endif
 
@@ -696,7 +699,10 @@
 endif
 
 ifdef CONFIG_CC_OPTIMIZE_FOR_DEBUG
-KBUILD_CFLAGS	+= -Og
+KBUILD_CFLAGS	+= -Og -Wno-maybe-uninitialized
+# Avoid false positives -Wmaybe-uninitialized
+# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78394
+KBUILD_CFLAGS	+= -Wno-maybe-uninitialized
 endif
 
 LTO_CFLAGS :=