ata: pata_ep93xx: use soc_device_match for UDMA modes

Replace ep93xx_chip_revision() with soc_device_match(), so
ep93xx_chip_revision() can be safetly dropped from exported functions.

Signed-off-by: Nikita Shubin <nikita.shubin@maquefel.me>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>