rt2x00: rt2800pci: use separate read_eeprom callback for SoC devices

Rename the 'rt2800pci_read_eeprom_soc function' to
'rt2800soc_read_eeprom' and use that directly in the
SoC specific 'rt2800_ops' structure. Also move the
'rt2800pci_eeprom_read' function into an 'ifdef PCI'
section and remove the 'rt2800pci_read_eeprom_soc'
call from that.

Additionally, remove the dummy inline eeprom functions.
Those are not used anymore.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>