soc/intel/apollolake: Use the new SPI driver interface

1. Define controller for fast SPI.
2. Separate out functions that are specific to SPI and flash controller
in different files.

BUG=chrome-os-partner:59832
BRANCH=None
TEST=Compiles successfully for reef.

Change-Id: If07db9d27bbf4f4eb6024175cb7753c6cf4fb793
Signed-off-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: https://review.coreboot.org/17562
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins)

src/soc/intel/apollolake/bootblock/bootblock.c

@@ -21,6 +21,7 @@
 #include <lib.h>
 #include <soc/iomap.h>
 #include <soc/cpu.h>
+#include <soc/flash_ctrlr.h>
 #include <soc/gpio.h>
 #include <soc/iosf.h>
 #include <soc/mmap_boot.h>
@@ -129,7 +130,7 @@ static void enable_spibar(void)
 	pci_write_config8(dev, PCI_COMMAND, val);
 
 	/* Initialize SPI to allow BIOS to write/erase on flash. */
-	spi_init();
+	spi_flash_init();
 }
 
 static void enable_pmcbar(void)