pata_falcon: Avoid type warnings from sparse

The zero day bot reported some sparse complaints in pata_falcon.c. E.g.

drivers/ata/pata_falcon.c:58:41: warning: cast removes address space '__iomem' of expression
drivers/ata/pata_falcon.c:58:41: warning: incorrect type in argument 1 (different address spaces)
drivers/ata/pata_falcon.c:58:41:    expected unsigned short volatile [noderef] [usertype] __iomem *port
drivers/ata/pata_falcon.c:58:41:    got unsigned short [usertype] *

The same thing shows up in 8 places, all told. Avoid this by removing
unnecessary type casts.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Michael Schmitz <schmitzmic@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Reported-by: kernel test robot <lkp@intel.com>
Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Finn Thain <fthain@linux-m68k.org>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>