spi: Few fix/improvement for spi-nxp-fspi

haibo.chen@oss.nxp.com <haibo.chen@oss.nxp.com> says:

Patch 1 introduce per-SoC clock rate limits for both SDR and DTR modes
        by adding max_sdr_rate and max_dtr_rate to nxp_fspi_devtype_data.
Patch 2 enter stop mode before reconfiguring MCR0 and DLL to follow
	FlexSPI reference manual initialization sequence
Patch 3 propagate clock reconfig failures in nxp_fspi_select_mem()

Link: https://patch.msgid.link/20260728-fspi-clock-v2-0-dbe786a4a6eb@nxp.com