uefi: x86: current (6.12) and edge (6.18): add Apple T2 patches

- from linux-t2 project: https://github.com/t2linux/linux-t2-patches
  - https://t2linux.org/
- x86: add .config hook `custom_kernel_config__applet2()`
- original patches from t2linux for 6.18 and 6.12
- rewrite patches against v6.18-rc4 and v6.12.57
  - `7001-drm-i915-fbdev-Discard-BIOS-framebuffers-exceeding-h.patch`
    needed special attention for correct patch attribution (missing From)
  - `1002-Put-apple-bce-in-drivers-staging` needs reordering to the
    top to avoid conflicts with EXTRAWIFI sed-based "patching"

Author: rpardini

config/sources/families/uefi-x86.conf

@@ -12,4 +12,59 @@ declare -g LINUXFAMILY="x86"
 declare -g ARCH="amd64"
 # shellcheck source=config/sources/families/include/uefi_common.inc
 source "${BASH_SOURCE%/*}/include/uefi_common.inc"
+
+# Extra branch "applet2" for uefi-x86 (Apple T2-based machines, all Intel)
+case "${BRANCH}" in
+
+	current | edge)
+		display_alert "Configuring for Apple T2-based machines" "x86: BRANCH=${BRANCH}" "info"
+
+		# Extra .config stuff for the Applet T2 stuff in this kernel
+		function custom_kernel_config__applet2() {
+			# From https://github.com/t2linux/linux-t2-patches/blob/6.18/extra_config ignore DRM_KUNIT_TEST & APFS_FS
+			opts_y+=(
+				BT_HCIUART_BCM
+				STAGING
+			)
+			opts_m+=(
+				APPLE_BCE
+				APPLE_GMUX
+				BRCMFMAC
+				BT_BCM
+				BT_HCIBCM4377
+				BT_HCIUART
+				HID_APPLETB_BL
+				HID_APPLETB_KBD
+				HID_APPLE
+				HID_MAGICMOUSE
+				DRM_APPLETBDRM
+				HID_SENSOR_ALS
+				SENSORS_APPLESMC
+				SND_PCM
+				APFS_FS
+			)
+		}
+
+		# Auto-grab patches from t2linux github if not already present
+		if [[ ! -d "${SRC}/patch/kernel/${KERNELPATCHDIR}" ]]; then
+			# Grab from github .tar.gz and extract there; patches are in the root of the archive
+			GH_URL="https://github.com/t2linux/linux-t2-patches/archive/refs/heads/${KERNEL_MAJOR_MINOR}.tar.gz"
+			display_alert "Fetching Apple T2 patches from" "GH_URL=${GH_URL}" "info"
+			mkdir -pv "${SRC}/patch/kernel/${KERNELPATCHDIR}"
+			curl -L "${GH_URL}" | tar -xz --strip-components=1 -C "${SRC}/patch/kernel/${KERNELPATCHDIR}"
+			tree "${SRC}/patch/kernel/${KERNELPATCHDIR}"
+			# remove any non-patch files and directories
+			# remove .github and .gitignore
+			rm -rf "${SRC}/patch/kernel/${KERNELPATCHDIR}/.github" "${SRC}/patch/kernel/${KERNELPATCHDIR}/.gitignore"
+			find "${SRC}/patch/kernel/${KERNELPATCHDIR}" -type f ! -name "*.patch" -delete
+			display_alert "Apple T2 patches downloaded to" "DIR=${SRC}/patch/kernel/${KERNELPATCHDIR}; go run rewrite-kernel-patches" "info"
+			exit 0
+		else
+			display_alert "Apple T2 patches already present in" "DIR=${SRC}/patch/kernel/${KERNELPATCHDIR}" "info"
+		fi
+
+		;;
+
+esac
+
 enable_extension "grub"