ssoc/intel/tigerlake: Use boolean for enable_c6dram

"enable_c6dram" needs only 2 "states" to be clearly defined.
C provides "true/false", so use it instead of using unsigned int.

Change-Id: Icff1b42ceb2e89cc0b2e7abab6743430c635db7b
Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/84155
Reviewed-by: Sean Rhodes <sean@starlabs.systems>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/tigerlake/chip.h

@@ -288,7 +288,7 @@ struct soc_intel_tigerlake_config {
 	bool eist_enable;
 
 	/* Enable C6 DRAM */
-	uint8_t enable_c6dram;
+	bool enable_c6dram;
 
 	/*
 	 * SerialIO device mode selection: