spi: nxp_fspi: reset the FLSHxCR1 registers

Reset the FLSHxCR1 registers to default value. ROM may set the register
value and it affects the SPI NAND normal functions.

Signed-off-by: Han Xu <han.xu@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>