Staging: ipack/bridges/tpci200: Protect device registers with spinlock.

Some of the device registers are accessed from both interrupt and
non-interrupt context.  To ensure proper read-modify-write modification
of these registers we can not use the  "global" tpci200 mutex.  Instead
a spin-lock is used.

Signed-off-by: Jens Taprogge <jens.taprogge@taprogge.org>
Signed-off-by: Samuel Iglesias Gonsalvez <siglesias@igalia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>