There is some repetitive code in the switch/case statements in
pci_bios_read() and pci_bios_write().  Factor out the BIOS function
IDs and the result widths to simplify the code.
Signed-off-by: NGeliang Tang <geliangtang@163.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>