bcma: move parsing of EEPROM into own function.

Move the parsing of the EEPROM data in scan function for one core into
an own function. Now we are able to use it in some other scan function
as well.

Acked-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>