lib/iommu-common.c: do not use 0xffffffffffffffffl for computing align_mask

Using a 64 bit constant generates "warning: integer constant is too
large for 'long' type" on 32 bit platforms. Instead use ~0ul and
BITS_PER_LONG.

Detected by Andrew Morton on ARMD.

Signed-off-by: Sowmini Varadhan <[e-mail]>
Cc: Benjamin Herrenschmidt <[e-mail]>
Cc: David S. Miller <[e-mail]>
Cc: Guenter Roeck <[e-mail]>
Cc: Rasmus Villemoes <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

lib/iommu-common.c

···
 	unsigned long align_mask = 0;
 
 	if (align_order > 0)
-		align_mask = 0xffffffffffffffffl >> (64 - align_order);
+		align_mask = ~0ul >> (BITS_PER_LONG - align_order);
 
 	/* Sanity check */
 	if (unlikely(npages == 0)) {