spi: spi-fsl-dspi: Fix casting warnings

spi: spi-fsl-dspi: Fix casting warnings

Sparse warnings:

drivers/spi/spi-fsl-dspi.c:283:17: warning: incorrect type in assignment (different base types)
drivers/spi/spi-fsl-dspi.c:283:17:    expected unsigned int [usertype]
drivers/spi/spi-fsl-dspi.c:283:17:    got restricted __be32 [usertype]
drivers/spi/spi-fsl-dspi.c:289:28: warning: cast to restricted __be32
drivers/spi/spi-fsl-dspi.c:289:28: warning: cast to restricted __be32
drivers/spi/spi-fsl-dspi.c:289:28: warning: cast to restricted __be32
drivers/spi/spi-fsl-dspi.c:289:28: warning: cast to restricted __be32
drivers/spi/spi-fsl-dspi.c:289:28: warning: cast to restricted __be32
drivers/spi/spi-fsl-dspi.c:289:28: warning: cast to restricted __be32
drivers/spi/spi-fsl-dspi.c:295:17: warning: incorrect type in assignment (different base types)
drivers/spi/spi-fsl-dspi.c:295:17:    expected unsigned int [usertype]
drivers/spi/spi-fsl-dspi.c:295:17:    got restricted __be16 [usertype]
drivers/spi/spi-fsl-dspi.c:301:28: warning: cast to restricted __be16
drivers/spi/spi-fsl-dspi.c:301:28: warning: cast to restricted __be16
drivers/spi/spi-fsl-dspi.c:301:28: warning: cast to restricted __be16
drivers/spi/spi-fsl-dspi.c:301:28: warning: cast to restricted __be16

Signed-off-by: Hardevsinh Palaniya <hardevsinh.palaniya@siliconsignals.io>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://patch.msgid.link/20241008055644.4900-2-hardevsinh.palaniya@siliconsignals.io
Signed-off-by: Mark Brown <broonie@kernel.org>