add checking the CONFIG_ENV_IS_IN_SPI_FLASH in Enbedded env

Fix the problem which cannot build the U-boot, if we only set
the CONFIG_ENV_IS_IN_SPI_FLASH.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Acked-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>

include/environment.h

@@ -107,7 +107,8 @@ extern unsigned long nand_env_oob_offset;
 #ifdef CONFIG_ENV_IS_EMBEDDED
 # if !defined(CONFIG_ENV_IS_IN_FLASH) && \
      !defined(CONFIG_ENV_IS_IN_NAND) && \
-     !defined(CONFIG_ENV_IS_IN_ONENAND)
+     !defined(CONFIG_ENV_IS_IN_ONENAND) && \
+     !defined(CONFIG_ENV_IS_IN_SPI_FLASH)
 #  error "CONFIG_ENV_IS_EMBEDDED not supported for your flash type"
 # endif
 #endif