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/configs/porter_defconfig b/configs/porter_defconfig
index 97b9e21..4708c74 100644
--- a/configs/porter_defconfig
+++ b/configs/porter_defconfig
@@ -23,7 +23,7 @@
 CONFIG_SPL_SYS_MALLOC_F_LEN=0x2000
 CONFIG_SPL=y
 CONFIG_SPL_SPI_FLASH_SUPPORT=y
-CONFIG_SPL_SPI_SUPPORT=y
+CONFIG_SPL_SPI=y
 CONFIG_SYS_LOAD_ADDR=0x50000000
 CONFIG_FIT=y
 CONFIG_BOOTDELAY=3