RT2560+RT2661: update the physical address in the RX descriptor after
bus_dmamap_load() in the case where the same mbuf is reloaded.
modify interrupt handlers to exit early and return 0 on shared interrupts.
RT2661:
flags for register TXRX_CSR4 were shifted one bit too much on the left.
this has probably affected short preamble support as well as hardware
multi-rate retries settings.
fix handling of the SIOCS80211CHANNEL ioctl in monitor mode:
don't call xxx_set_chan() if the interface is not up&running.
Tested with the following hw:
ral0 at pci5 dev 0 function 0: Ralink Technologies RT2561 802.11b/g (rev. 0x00)
ral0: interrupting at ioapic0 pin 20 (irq 10)
ral0: 802.11 address 00:80:5a:4f:ab:e2
ral0: MAC/BBP RT2561C, RF RT2527
b2af3e5bc6