[ARM] 5211/2: fix a couple warnings from BUG() usage

When CONFIG_DEBUG_BUGVERBOSE is not set, we get warnings such as:

arch/arm/mm/ioremap.c: In function ‘remap_area_pte’:
arch/arm/mm/ioremap.c:67: warning: control reaches end of non-void function
mm/bootmem.c: In function ‘mark_bootmem’:
mm/bootmem.c:321: warning: control reaches end of non-void function
fs/dcache.c: In function ‘d_materialise_unique’:
fs/dcache.c:1875: warning: control reaches end of non-void function
fs/nfs/client.c: In function ‘nfs_sockaddr_match_ipaddr’:
fs/nfs/client.c:251: warning: control reaches end of non-void function
block/cfq-iosched.c: In function ‘cfq_async_queue_prio’:
block/cfq-iosched.c:1501: warning: control reaches end of non-void function

Signed-off-by: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>