spi: Rename SPI_SUPPORT to SPI

Rename these options so that CONFIG_IS_ENABLED can be used with them.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/mach-mediatek/spl.c b/arch/arm/mach-mediatek/spl.c
index 45a041b..d3cda94 100644
--- a/arch/arm/mach-mediatek/spl.c
+++ b/arch/arm/mach-mediatek/spl.c
@@ -31,7 +31,7 @@
 
 u32 spl_boot_device(void)
 {
-#if defined(CONFIG_SPL_SPI_SUPPORT)
+#if defined(CONFIG_SPL_SPI)
 	return BOOT_DEVICE_SPI;
 #elif defined(CONFIG_SPL_MMC)
 	return BOOT_DEVICE_MMC1;