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