power: reset: convert to CFLAGS_MODULE

Upstream has removed the support for EXTRA_CFLAGS in [1]. The driver
here is converted to use CFLAGS_MODULE as a direct replacement. No
functional changes expected from this patch.

Bug: 412122604
Link: https://git.kernel.org/torvalds/c/e966ad0edd00 [1]
Change-Id: Iadfc492cef5ab219467f9df739f4c66eabd1a1c3
Signed-off-by: Carlos Llamas <[email protected]>
diff --git a/Makefile b/Makefile
index 9e5945f..d0ee17c 100644
--- a/Makefile
+++ b/Makefile
@@ -7,4 +7,4 @@
 
 modules modules_install clean:
 	$(MAKE) -C $(KERNEL_SRC) M=$(M) \
-	EXTRA_CFLAGS="$(EXTRA_CFLAGS)" KBUILD_EXTRA_SYMBOLS="$(EXTRA_SYMBOLS)" $(@)
+	CFLAGS_MODULE="$(CFLAGS_MODULE)" KBUILD_EXTRA_SYMBOLS="$(EXTRA_SYMBOLS)" $(@)