eeprom: merge cmdline parsing of eeprom commands

eeprom: merge cmdline parsing of eeprom commands

Merge the parsing of layout aware and layout unaware eeprom commands into
one parsing function. With this change, layout aware commands now follow
the eeprom read and eeprom write conventions of making i2c bus and i2c address
parameters optional.

Cc: Heiko Schocher <[email protected]>
Cc: Marek Vasut <[email protected]>
Cc: Simon Glass <[email protected]>
Cc: Igor Grinberg <[email protected]>
Cc: Tom Rini <[email protected]>
Signed-off-by: Nikita Kiryanov <[email protected]>