FRV: bitops: Change the bitmap index from int to unsigned long

Change the index to unsigned long in all bitops for [frv]

Signed-off-by: Justin Chen <justin.chen@hp.com>
Reviewed-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>