ide: remove unused variables from drivers/ide/ppc/pmac.c

Removes these warnings:

/home/sfr/kernels/linus/drivers/ide/ppc/pmac.c: In function 'pmac_ide_dma_check':
/home/sfr/kernels/linus/drivers/ide/ppc/pmac.c:1807: warning: unused variable 'map'
/home/sfr/kernels/linus/drivers/ide/ppc/pmac.c:1805: warning: unused variable 'pmif'

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: paulus@samba.org
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>