nfp: only use direct firmware requests

request_firmware() will fallback to user space helper and may cause
long delays when driver is loaded if udev doesn't correctly handle
FW requests.  Since we never really made use of the user space
helper functionality switch to the simpler request_firmware_direct()
call.  The side effect of this change is that no warning will be
printed when the FW image does not exists.  To help users figure
out which FW file is missing print a info message when we request
each file.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>