mwlwifi: Fix loading with backports v5.3

This adds a vendor command policy which is enforced since mac80211 from
kernel 5.3

Fixes: 928e893a11 ("mac80211: Update to version 5.3-rc4-1")
Signed-off-by: Boris Krasnovskiy <boris.krasnovskiy@lairdtech.com>

package/kernel/mwlwifi/Makefile

@@ -8,7 +8,7 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=mwlwifi
-PKG_RELEASE=1
+PKG_RELEASE=2
 
 PKG_LICENSE:=ISC
 PKG_LICENSE_FILES:=

package/kernel/mwlwifi/patches/001-vendor_command_policy.patch

@@ -0,0 +1,19 @@
+mac80211 from kernel 5.3 and later checks the new policy attribute.
+
+--- a/vendor_cmd.c
++++ b/vendor_cmd.c
+@@ -92,12 +92,14 @@ static const struct wiphy_vendor_command
+ 			  .subcmd = MWL_VENDOR_CMD_SET_BF_TYPE},
+ 		.flags = WIPHY_VENDOR_CMD_NEED_NETDEV,
+ 		.doit = mwl_vendor_cmd_set_bf_type,
++		.policy = mwl_vendor_attr_policy,
+ 	},
+ 	{
+ 		.info = { .vendor_id = MRVL_OUI,
+ 			  .subcmd = MWL_VENDOR_CMD_GET_BF_TYPE},
+ 		.flags = WIPHY_VENDOR_CMD_NEED_NETDEV,
+ 		.doit = mwl_vendor_cmd_get_bf_type,
++		.policy = mwl_vendor_attr_policy,
+ 	}
+ };
+