pit: Bump the EC SPI bus speed up to 5 MHz

That speed is used with U-Boot instead of the more conservative 500 KHz.

Change-Id: Ie9d79db3b52b88c1f3bfec1745634ae6bdc9f4ee
Signed-off-by: Gabe Black <gabeblack@google.com>
Reviewed-on: https://gerrit.chromium.org/gerrit/63193
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Commit-Queue: Gabe Black <gabeblack@chromium.org>
Tested-by: Gabe Black <gabeblack@chromium.org>
Reviewed-on: http://review.coreboot.org/4386
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>

src/mainboard/google/pit/romstage.c

@@ -126,7 +126,7 @@ static void setup_ec(void)
 {
 	/* SPI2 (EC) is slower and needs to work in half-duplex mode with
 	 * single byte bus width. */
-	clock_set_rate(PERIPH_ID_SPI2, 500000);
+	clock_set_rate(PERIPH_ID_SPI2, 5000000);
 	exynos_pinmux_spi2();
 }