Staging: dt3155: allocator.c: sparse cleanups

Make prototypes match implementation
Use gfp_t flags not int prio

Still a couple of sparse warnings left

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Simon Horman <horms@verge.net.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>