Kbuild: disable Werror

clang 13 enables the warning -Wunused-but-set-variable by default which
lets the build fail. Disable Werror so it stays a warning.

Change-Id: I46af1c34e006162a4a39a4cb7399f566f5b276b7
diff --git a/Kbuild b/Kbuild
index 5167ca1..4753220 100644
--- a/Kbuild
+++ b/Kbuild
@@ -2269,7 +2269,6 @@
 
 cppflags-y +=	-DANI_OS_TYPE_ANDROID=6 \
 		-Wall\
-		-Werror\
 		-D__linux__
 
 cppflags-$(CONFIG_PTT_SOCK_SVC_ENABLE) += -DPTT_SOCK_SVC_ENABLE