spi: xilinx_spi: Trivial fixes in axi qspi driver

Use __func__ instead for function name in debug.
Use Linux style u32 instead of uint32_t.

Signed-off-by: T Karthik Reddy <t.karthik.reddy@xilinx.com>
Acked-by: Ashok Reddy Soma <ashok.reddy.soma@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>