MAINTAINERS: SPI: Add mailing list imx@lists.linux.dev for nxp spi drivers

Add mailing list imx@lists.linux.dev for nxp spi drivers(qspi, fspi and
dspi).

Signed-off-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Stefan Wahren <wahrenst@gmx.net>
Link: https://patch.msgid.link/20240905155230.1901787-1-Frank.Li@nxp.com


Signed-off-by: Mark Brown <broonie@kernel.org>