SPL: ext: remove redundant ifdef statement

Remove redundant #if defined(CONFIG_SPL_OS_BOOT) statement around
getenv() calls in spl_load_image_ext_os().

The whole function is surrounded by #ifdef CONFIG_SPL_OS_BOOT.

No functional change.

Signed-off-by: Petr Kulhavy <brain@jikos.cz>
CC: Guillaume GARDET <guillaume.gardet@free.fr>
Acked-by:  Guillaume GARDET <guillaume.gardet@free.fr>
diff --git a/common/spl/spl_ext.c b/common/spl/spl_ext.c
index ade5496..89ac4f4 100644
--- a/common/spl/spl_ext.c
+++ b/common/spl/spl_ext.c
@@ -88,8 +88,7 @@
 #endif
 		return -1;
 	}
-
-#if defined(CONFIG_SPL_ENV_SUPPORT) && defined(CONFIG_SPL_OS_BOOT)
+#if defined(CONFIG_SPL_ENV_SUPPORT)
 	file = getenv("falcon_args_file");
 	if (file) {
 		err = ext4fs_open(file, &filelen);