Cache downloads based on checksum

Since many boards use the same ME firmware, we could save
everyone's bandwidth and time by caching the update files.

Signed-off-by: Riku Viitanen <riku.viitanen@protonmail.com>

.gitignore

@@ -39,7 +39,7 @@
 /version
 /versiondate
 /blobs/app/
-/blobs/vendorupdate
+/blobs/cache/
 *me.bin
 /mrc/
 /util/nvmutil/nvm

resources/scripts/update/blobs/download

@@ -11,6 +11,7 @@ ec_hash=""
 dl_hash=""
 dl_url=""
 dl_url_bkup=""
+dl_path=""
 e6400_vga_dl_hash=""
 e6400_vga_dl_url=""
 e6400_vga_dl_url_bkup=""
@@ -21,7 +22,6 @@ cbdir="coreboot/default"
 cbcfgsdir="resources/coreboot"
 boarddir=""
 blobdir="blobs"
-dl_path="${blobdir}/vendorupdate"
 appdir="${blobdir}/app"
 _7ztest="a"
 mecleaner="$(pwd)/me_cleaner/me_cleaner.py"
@@ -431,6 +431,9 @@ fetch_update()
 		return 1
 	fi
 
+	dl_path=${blobdir}/cache/${dlsum}
+	mkdir -p ${blobdir}/cache
+
 	vendor_checksum ${dlsum} || \
 		wget ${dl} -O ${dl_path} || wget ${dl_bkup} -O ${dl_path}