driver: spi: fsl-qspi: remove compile Warnings

Warnins log:
drivers/spi/fsl_qspi.c: In function ‘qspi_ahb_read’:
drivers/spi/fsl_qspi.c:400:16: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
  memcpy(rxbuf, (u8 *)(priv->cur_amba_base + priv->sf_addr), len);

Signed-off-by: Yunhui Cui <yunhui.cui@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>