bcma: init sprom struct earlier

The PCIe host driver and the chip common initialisation accesses the
sprom struct, but it is not initialized when these functions are run.
Move the sprom parsing up in to do it earlier.
As we need the chip common core rev and some other attributes from the
chip common core, the early initialization is done before accessing the
sprom.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>