mmc: env: Unify the U_BOOT_ENV_LOCATION conditions

The declaration of U_BOOT_ENV_LOCATION() uses a different #ifdef
condition from the code it calls. Use the same condition to avoid a
build warning if CONFIG_CMD_SAVEENV is disabled.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
diff --git a/env/mmc.c b/env/mmc.c
index cb14bbb..da84cdd 100644
--- a/env/mmc.c
+++ b/env/mmc.c
@@ -495,7 +495,7 @@
 	.location	= ENVL_MMC,
 	ENV_NAME("MMC")
 	.load		= env_mmc_load,
-#ifndef CONFIG_SPL_BUILD
+#if defined(CONFIG_CMD_SAVEENV) && !defined(CONFIG_SPL_BUILD)
 	.save		= env_save_ptr(env_mmc_save),
 	.erase		= ENV_ERASE_PTR(env_mmc_erase)
 #endif