board/freescale/mpc8610hpcd/mpc8610hpcd.c: Fix GCC 4.6 build warning

Fix:
mpc8610hpcd.c: In function 'pci_init_board':
mpc8610hpcd.c:238:15: warning: variable 'pordevsr' set but not used
[-Wunused-but-set-variable]

Signed-off-by: Wolfgang Denk <wd@denx.de>
Cc: Kumar Gala <galak@kernel.crashing.org>
Acked-by: Kumar Gala <galak@kernel.crashing.org>