ata: pata_samsung_cf: add missing __iomem annotation

Added missing __iomem annotation and staticized local symbol
in order to fix the following sparse warnings:

drivers/ata/pata_samsung_cf.c:244:14: warning: symbol 'pata_s3c_data_xfer' was not declared. Should it be static?
drivers/ata/pata_samsung_cf.c:423:20: warning: incorrect type in argument 1 (different address spaces)
drivers/ata/pata_samsung_cf.c:423:20:    expected void const volatile [noderef] <asn:2>*addr
drivers/ata/pata_samsung_cf.c:423:20:    got void *
drivers/ata/pata_samsung_cf.c:425:9: warning: incorrect type in argument 2 (different address spaces)
drivers/ata/pata_samsung_cf.c:425:9:    expected void volatile [noderef] <asn:2>*addr
drivers/ata/pata_samsung_cf.c:425:9:    got void *
drivers/ata/pata_samsung_cf.c:448:37: warning: incorrect type in argument 1 (different address spaces)
drivers/ata/pata_samsung_cf.c:448:37:    expected void *s3c_ide_regbase
drivers/ata/pata_samsung_cf.c:448:37:    got void [noderef] <asn:2>*ide_addr
drivers/ata/pata_samsung_cf.c:463:37: warning: incorrect type in argument 1 (different address spaces)
drivers/ata/pata_samsung_cf.c:463:37:    expected void *s3c_ide_regbase
drivers/ata/pata_samsung_cf.c:463:37:    got void [noderef] <asn:2>*ide_addr

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Tejun Heo <tj@kernel.org>