parisc: sba_iommu: fix build bug when CONFIG_PARISC_AGP=y

CC      drivers/parisc/sba_iommu.o
drivers/parisc/sba_iommu.c:1373: error: expected identifier or '('
before '}' token
make[2]: *** [drivers/parisc/sba_iommu.o] Error 1
make[1]: *** [drivers/parisc] Error 2
make: *** [drivers] Error 2

Don't know how this has gone missed for so long... clearly I need
to do builds on my C8000 more often.

Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>