Cleanups for the PS3 vuart driver.

- Hide driver private data from external interface with new structure
  ps3_vuart_port_priv.
- Fix masking bug in ps3_vuart_get_interrupt_status().
- Add new helper routine ps3_vuart_clear_rx_bytes() to flush rx buffer.
- Add new variable probe_mutex to serialize probe and destroy routines.
- Rename some symbols.
- Add platform check in ps3_vuart_bus_init().
Signed-off-by: NGeoff Levand <geoffrey.levand@am.sony.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

PS3: Add a shutdown method to the PS3's virtual uart port driver framework
Signed-off-by: NGeert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Signed-off-by: NGeoff Levand <geoffrey.levand@am.sony.com>
Cc: James Simmons <jsimmons@infradead.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Move the structures and routines needed for PS3 vuart port device registration
to asm-powerpc/ps3.h.
Signed-off-by: NGeoff Levand <geoffrey.levand@am.sony.com>
Acked-by: NArnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Adds support for the PS3 virtual UART (vuart).  The vuart provides a
bi-directional byte stream data link between logical partitions.

This is needed for the ps3 graphics driver and the ps3 power
control support to be able to communicate with the lv1 policy
module.
Signed-off-by: NGeoff Levand <geoffrey.levand@am.sony.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NPaul Mackerras <paulus@samba.org>