Convert musb fifo to 8bit to allow 8/16/32bit access

MUSB allows reading and writing to the fifo in 32/16/8 bit
width. The Linux kernel does this sometimes, most usually at
the end of writing the packet to allow packet to end at a
odd bytecount.

Convert the fifo to 8bit allows removing lots of shifts
which shows that the fifo is more natural as 8bit.

While at it, add multiple missing register definitions and
and cleanup debug prints.

Signed-off-by: Riku Voipio <riku.voipio@nokia.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>