soc/intel/apollolake: Hook up Legacy 8254 Timer

Hook Timer8254ClkSetting to `legacy_8254_timer` cmos option. If that
isn't set, fallback to the `USE_LEGACY_8254_TIMER` Kconfig option.

Signed-off-by: Sean Rhodes <sean@starlabs.systems>
Change-Id: I4f91cc2c8f48e9da47399059386092314b631b08
Reviewed-on: https://review.coreboot.org/c/coreboot/+/64522
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Felix Singer <felixsinger@posteo.net>

src/soc/intel/apollolake/chip.c

@@ -721,6 +721,10 @@ void platform_fsp_silicon_init_params_cb(FSPS_UPD *silupd)
 	if (is_devfn_enabled(PCH_DEVFN_SATA))
 		silconfig->SataSalpSupport = !(cfg->DisableSataSalpSupport);
 
+	/* 8254 Timer */
+	bool use_8254 = get_uint_option("legacy_8254_timer", CONFIG(USE_LEGACY_8254_TIMER));
+	silconfig->Timer8254ClkSetting = use_8254;
+
 	mainboard_silicon_init_params(silconfig);
 }