spi: Add zynq qspi controller driver

spi: Add zynq qspi controller driver

Added zynq qspi controller driver for Xilinx Zynq APSOC,
this driver is driver-model driven with devicetree support.

=> sf probe
SF: Detected S25FL128S_64K with page size 256 Bytes, erase size 64 KiB, total 16 MiB
=> mw.b 0x100 0xCC 0x1000000
=> sf update 0x100 0x0 0x1000000
device 0 whole chip
16777216 bytes written, 0 bytes skipped in 59.842s, speed 289262 B/s
=> sf read 0x3000000 0x0 0x1000000
device 0 whole chip
SF: 16777216 bytes @ 0x0 Read: OK
=> cmp.b 0x3000000 0x100 0x1000000
Total of 16777216 byte(s) were the same

Signed-off-by: Jagan Teki <jteki@openedev.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Cc: Michal Simek <michal.simek@xilinx.com>
Acked-by: Siva Durga Prasad Paladugu <sivadur@xilinx.com>
Tested-by: Jagan Teki <jteki@openedev.com>