was major changes to initialize RF chipset and set H/W registers and
removed a lot of magic numbers on code. Details are as follows:
- uses the endpoint 0x89 to get TX status information which used to
get TX complete or retry numbers or get a beacon interrupt. It's
only valuable for RTL8187B.
- removes urtw_write[8|16|32]_i functions that it's useless now.
- uses ic->ic_updateslot to set SLOT, SIFS, DIES, EIFS, CW_VAL
registers that doesn't set these whenever the channel is changed.
- code for initializing RF chipset for RTL8187B changed a lot that
there was many problems on TX transfers so it doesn't work properly
even if just for a ping/pong. Now it becomes more stable than
before that TX throughputs using netperf(1) were about 15 ~ 17Mbps/s
though sometimes it encounters packet losses.
- removes a lot of magic numbers that in the previous all of
representing RX and TX descriptors were consisted of magic numbers
and structures. It'd be more readable rather than before.
- calculates TX duration more accurately for urtw(4) devices.
- style(9)
