This patch introduces one devres API of devres_for_each_res
so that the device's driver can iterate each resource it has
interest in.

The firmware loader will use the API to get each firmware name
from the device instance.
Signed-off-by: NMing Lei <ming.lei@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>