Some BIOSes set the PCI cacheline size to zero for the card; the ath5k
driver fixes it to a reasonable in PCI config space, but failed to
correct the internal value it had already read. This resulted in
divide-by-zero errors when cacheline-aligning various data structures.

Fix by setting the internal cachelsz to a sane value at the same time
as we write that value to PCI config space.

Signed-off-by: Marty Connor <mdc@etherboot.org>