GPIO: add new Xilinx driver for powerpc

GPIO: add new Xilinx driver for powerpc

This driver supports the Xilinx XPS GPIO IP core which has the typical
GPIO features.

Signed-off-by: Kiran Sutariya <[email protected]>
Signed-off-by: John Linn <[email protected]>
Cc: David Brownell <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Kumar Gala <[email protected]>
Cc: "Grant Likely" <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>