tegra: spi: rename tegra SPI drivers

Rename tegra SPI drivers to tegra20_flash and tegra20_slink in
preparation for commonization and addition of tegra114_spi.

Signed-off-by: Allen Martin <amartin@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
diff --git a/include/configs/trimslice.h b/include/configs/trimslice.h
index 0644f7a..b925314 100644
--- a/include/configs/trimslice.h
+++ b/include/configs/trimslice.h
@@ -46,7 +46,7 @@
 #define CONFIG_BOARD_EARLY_INIT_F
 
 /* SPI */
-#define CONFIG_TEGRA_SPI
+#define CONFIG_TEGRA20_SFLASH
 #define CONFIG_SPI_FLASH
 #define CONFIG_SPI_FLASH_WINBOND
 #define CONFIG_SF_DEFAULT_MODE		SPI_MODE_0