can: Topcliff: Add PCH_CAN driver.

CAN driver of Topcliff PCH

Topcliff PCH is the platform controller hub that is going to be used in
Intel's upcoming general embedded platform. All IO peripherals in
Topcliff PCH are actually devices sitting on AMBA bus.
Topcliff PCH has CAN I/F. This driver enables CAN function.

Signed-off-by: Masayuki Ohtake <masa-korg@dsn.okisemi.com>
Signed-off-by: David S. Miller <davem@davemloft.net>