usb: r8a66597-udc unaligned fifo fix

Rework the r8a66597-udc fifo code to avoid unaligned accesses.

Without this patch unaligned exceptions will degrade the
USB performance. The exceptions come from the fact that
the usb fifo data buffers may be misaligned.

This patch updates the fifo access code to only use
insl()/outsl() and insw()/outsw() in the case of properly
aligned data buffers. The fallback case is that inl()/inw()
are used for misaligned buffer reads together with outb()
that is used for misaligned buffer writes.

Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>