iwlwifi: fix the gcc build

- Only apply the previously added CWARNFLAGS to `drv.c` instead of the
  whole module.
- Only apply `-Wno-initializer-overrides` to CWARNFLAGS in the clang
  scenario as it's not supported with gcc.

This fixes building the module with gcc and avoids accidentally
introducing tech debt with the module, in the event other issues are
accidentally introduced.

MFC after:	3 days
Fixes:		6b627f8858 ("iwlwifi: update Intel's mvm/mld drivers")
Differential Revision:	https://reviews.freebsd.org/D53591

1 files changed, 2 insertions, 2 deletions

diff --git a/sys/modules/iwlwifi/Makefile b/sys/modules/iwlwifi/Makefile
index 5d4830537a0b..6fe64a611900 100644
--- a/sys/modules/iwlwifi/Makefile
+++ b/sys/modules/iwlwifi/Makefile
@@ -91,7 +91,7 @@ CFLAGS+=	-DCONFIG_IWLWIFI_DEVICE_TRACING=1
 #CFLAGS+=	-DCONFIG_THERMAL=1
 #CFLAGS+=	-DCONFIG_EFI=1
 
-# XXX-BZ how to do this just for pcie/drv.c (and gcc vs. clang)?
-CFLAGS += -Wno-override-init -Wno-initializer-overrides
+CWARNFLAGS.clang.drv.c+=	-Wno-initializer-overrides
+CWARNFLAGS.drv.c+=		-Wno-override-init ${CWARNFLAGS.${COMPILER_TYPE}.${.IMPSRC:T}}
 
 .include <bsd.kmod.mk>