block: remove bvec_to_phys

We only use it in biovec_phys_mergeable and a m68k paravirt driver,
so just opencode it there.  Also remove the pointless unsigned long cast
for the offset in the opencoded instances.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

arch/m68k/emu/nfblock.c

@@ -73,7 +73,7 @@ static blk_qc_t nfhd_make_request(struct request_queue *queue, struct bio *bio)
 		len = bvec.bv_len;
 		len >>= 9;
 		nfhd_read_write(dev->id, 0, dir, sec >> shift, len >> shift,
-				bvec_to_phys(&bvec));
+				page_to_phys(bvec.bv_page) + bvec.bv_offset);
 		sec += len;
 	}
 	bio_endio(bio);