linux-firmware: switch back to git protocol from https for download

Using HTTPS breaks the download on Debian Wheezy. The switch was an
unintended side effect of the backport from LEDE.

Also, fix the commit message of the backport patch (mwlwifi is not updated
anymore since the last OpenWrt base upgrade).

Fixes #919

patches/openwrt/0007-mac80211-hostapd-iw-.-update.patch

@@ -16,7 +16,6 @@ LEDE 42f559ed70897a7b74dd3e6293b42e6d2e511eaa:
 * iw
 * linux-firmware
 * mt76
-* mwlwifi
 
 diff --git a/package/firmware/ath10k-firmware/Makefile b/package/firmware/ath10k-firmware/Makefile
 index b03d644..624da6a 100644
@@ -271,16 +270,14 @@ index b03d644..624da6a 100644
 +$(eval $(call BuildPackage,ath10k-firmware-qca99x0-ct))
 +$(eval $(call BuildPackage,ath10k-firmware-qca9984-ct))
 diff --git a/package/firmware/linux-firmware/Makefile b/package/firmware/linux-firmware/Makefile
-index 2fcd93b..7a2e977 100644
+index 2fcd93b..ae5894c 100644
 --- a/package/firmware/linux-firmware/Makefile
 +++ b/package/firmware/linux-firmware/Makefile
-@@ -16,10 +16,10 @@ PKG_SOURCE_PROTO:=git
- PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz
+@@ -17,9 +17,9 @@ PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz
  PKG_SOURCE_SUBDIR:=$(PKG_NAME)-$(PKG_SOURCE_VERSION)
  PKG_BUILD_DIR:=$(BUILD_DIR)/$(PKG_SOURCE_SUBDIR)
--PKG_SOURCE_URL:=git://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git
+ PKG_SOURCE_URL:=git://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git
 -PKG_MIRROR_MD5SUM:=ca4d289ad9380471cae376fc7dd3660a
-+PKG_SOURCE_URL:=https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git
 +PKG_MIRROR_MD5SUM:=8d44332359de89b1936b4ff608a72614
  
 -PKG_MAINTAINER:=Felix Fietkau <nbd@openwrt.org>