soc/intel/cannonlake: Drop unnecessary guard

The MRC cache driver assumes BOOT_DEVICE_MEMORY_MAPPED=y already. This
is to ease factoring out common code across seven Intel platforms.

Change-Id: I0598cb18b456e10789b2a42792fbfa2639cdd2c4
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50951
Reviewed-by: Michael Niewöhner <foss@mniewoehner.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/cannonlake/bootblock/cpu.c

@@ -6,7 +6,5 @@
 void bootblock_cpu_init(void)
 {
 	/* Temporarily cache the memory-mapped boot media. */
-	if (CONFIG(BOOT_DEVICE_MEMORY_MAPPED) &&
+	fast_spi_cache_bios_region();
-		CONFIG(BOOT_DEVICE_SPI_FLASH))
-		fast_spi_cache_bios_region();
 }