[][MAC80211][build][Fix patch fail]

[Description]
Fix patch fail
Add symbolic link of mt76-vendor for unified sigma support.
Remove unnecessary compiler flag in MT76 makefile

[Release-log]
N/A

Change-Id: Ia4e297c0648a77c4e500d926fb617cba6a1a85fb
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/6140808
diff --git a/autobuild_mac80211_release/0003-master-mt76-makefile-for-new-chip.patch b/autobuild_mac80211_release/0003-master-mt76-makefile-for-new-chip.patch
index f9ee251..2eec36f 100644
--- a/autobuild_mac80211_release/0003-master-mt76-makefile-for-new-chip.patch
+++ b/autobuild_mac80211_release/0003-master-mt76-makefile-for-new-chip.patch
@@ -115,13 +115,11 @@
  define KernelPackage/mt7921e/install
  	$(INSTALL_DIR) $(1)/lib/firmware/mediatek
  	cp \
-@@ -489,5 +555,8 @@ $(eval $(call KernelPackage,mt7921-common))
+@@ -489,5 +555,6 @@ $(eval $(call KernelPackage,mt7921-common))
  $(eval $(call KernelPackage,mt7921u))
  $(eval $(call KernelPackage,mt7921s))
  $(eval $(call KernelPackage,mt7921e))
-+ifdef CONFIG_PACKAGE_kmod-bersa
 +$(eval $(call KernelPackage,bersa))
-+endif
  $(eval $(call KernelPackage,mt76))
  $(eval $(call BuildPackage,mt76-test))
 --