support/scripts/genimage.sh: drop gzip compression

Commit 6889056f1eb4 (support/scripts/genimage.sh: support creating a bmap
image) added unconditional gzip compression of the genimage outputs if
bmap-tools is enabled, which is problematic for a number of reasons:

- The gzip invocation is not reproducable (E.G. does not use -n)

- The original file is removed, dropping the sparse info

- It hardcodes policy, E.G.  bmap supports a number of different compression
  algorithms / compression may not be desired for all images / different
  compression levels may be desired

So drop the compression step.  If desired, compression can be done with a
post-image script.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Acked-by: TIAN Yuanhao <tianyuanhao3@163.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

support/scripts/genimage.sh

@@ -54,6 +54,5 @@ if grep -Eq "^BR2_PACKAGE_HOST_BMAP_TOOLS=y$" "${BR2_CONFIG}"; then
 			continue
 		fi
 		bmaptool create "${image_path}" -o "${image_path}.bmap"
-		gzip -c "${image_path}" > "${image_path}.gz"
 	done < <(grep '^image ' "${GENIMAGE_CFG}" | cut -d ' ' -f 2)
 fi