kernel.bbclass: allow uncompressed initramfs archives
The code failed to copy the initramfs in case it was a plain
cpio archive.
(From OE-Core rev:
7dbdb4ea91aa027866da2bd46c65fe65a25c848f)
(From OE-Core rev:
0d65292296ed9fb82e7bfbcca42d4b7a39ba6ca9)
Signed-off-by: Andreas Oberritter <obi@opendreambox.org>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Armin Kuster <akuster808@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>