spi: Remove the spi_set_speed and spi_cs_is_valid functions.

spi_set_speed was never implemented, and spi_cs_is_valid was only implemented
as a stub and never called.

BUG=None
TEST=Built for rambi, falco, and peach_pit.
BRANCH=None

Original-Change-Id: If30c2339f5e0360a5099eb540fab73fb23582905
Original-Signed-off-by: Gabe Black <gabeblack@google.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/192045
Original-Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Original-Tested-by: Gabe Black <gabeblack@chromium.org>
Original-Reviewed-by: David Hendricks <dhendrix@chromium.org>
Original-Commit-Queue: Gabe Black <gabeblack@chromium.org>
(cherry picked from commit 98c1f6014c)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: Iebdb2704ee81aee432c83ab182246d31ef52a6b6
Reviewed-on: http://review.coreboot.org/7707
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Tested-by: build bot (Jenkins)

src/soc/intel/baytrail/spi.c

@@ -266,12 +266,6 @@ static void ich_set_bbar(uint32_t minaddr)
 	writel_(ichspi_bbar, cntlr.bbar);
 }
 
-int spi_cs_is_valid(unsigned int bus, unsigned int cs)
-{
-	printk(BIOS_DEBUG, "spi_cs_is_valid used but not implemented\n");
-	return 0;
-}
-
 struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs)
 {
 	ich_spi_slave *slave = malloc(sizeof(*slave));

src/soc/intel/fsp_baytrail/spi.c

@@ -264,12 +264,6 @@ static void ich_set_bbar(uint32_t minaddr)
 	writel_(ichspi_bbar, cntlr.bbar);
 }
 
-int spi_cs_is_valid(unsigned int bus, unsigned int cs)
-{
-	printk(BIOS_DEBUG, "spi_cs_is_valid used but not implemented\n");
-	return 0;
-}
-
 struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs)
 {
 	ich_spi_slave *slave = malloc(sizeof(*slave));

src/soc/samsung/exynos5420/spi.c

@@ -133,11 +133,6 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs)
 	return &eslave->slave;
 }
 
-int spi_cs_is_valid(unsigned int bus, unsigned int cs)
-{
-	return bus > 0 && bus < 3;
-}
-
 void spi_cs_activate(struct spi_slave *slave)
 {
 	struct exynos_spi *regs = to_exynos_spi(slave)->regs;