spi: spi-nxp-fspi: correct the comment for the DLL config

Current DLL config is just to use the default setting, this means
enable the DLL override mode, and use 1 fixed delay cell in the
DLL delay chain, not means "reset" the DLL, so correct this to
avoid confuse.
Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
Link: https://lore.kernel.org/r/20230322090451.3179431-1-haibo.chen@nxp.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-nxp-fspi.c

@@ -997,7 +997,11 @@ static int nxp_fspi_default_setup(struct nxp_fspi *f)
 	/* Disable the module */
 	fspi_writel(f, FSPI_MCR0_MDIS, base + FSPI_MCR0);
 
-	/* Reset the DLL register to default value */
+	/*
+	 * Config the DLL register to default value, enable the slave clock delay
+	 * line delay cell override mode, and use 1 fixed delay cell in DLL delay
+	 * chain, this is the suggested setting when clock rate < 100MHz.
+	 */
 	fspi_writel(f, FSPI_DLLACR_OVRDEN, base + FSPI_DLLACR);
 	fspi_writel(f, FSPI_DLLBCR_OVRDEN, base + FSPI_DLLBCR);