ath9k: remove dummy PCI "retry timeout" fix

Remove the PCI retry timeout code as that was just taken from ipw2100
due to historical reasons but in reality its a no-op, additionally its
simply incorrect as each PCI devices has its own custom PCI configuration
space on PCI config space >= 0x40. Not to mention we were trying to write
0 to a place that already has 0 on it.

Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Ben Cahill <ben.m.cahill@intel.com>
Cc: Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
Tested-by: Adel Gadllah <adel.gadllah@gmail.com>
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>