linux-firmware: make the main package depend on all sub-packages

linux-firmware: make the main package depend on all sub-packages

Whilst splitting out specific large firmware blobs is a good move for space
saving, it makes installing "all the firmware" tricky.

Make linux-firmware depend on all of the separated packages so that installing
that pulls in all of the sub-packages.

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>