intel/skylake: Run spi_init as early as possible in ramstage

spi_init should be run early enough in ramstage so that any init
calls (e.g. mainboard_ec_init) that write on flash have right
permissions set.

Change-Id: I9cd3dc723387757951acd40449d4a41986836d2a
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/15235
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>

src/soc/intel/skylake/flash_controller.c

@@ -433,5 +433,5 @@ static void spi_init_cb(void *unused)
 	spi_init();
 }
 
-BOOT_STATE_INIT_ENTRY(BS_DEV_ENABLE, BS_ON_EXIT, spi_init_cb, NULL);
+BOOT_STATE_INIT_ENTRY(BS_PRE_DEVICE, BS_ON_ENTRY, spi_init_cb, NULL);
 #endif