common: env_common: make env_get_char_spec __weak

Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>

common/env_common.c

@@ -27,12 +27,10 @@ struct hsearch_data env_htab = {
 	.change_ok = env_flags_validate,
 };
 
-static uchar __env_get_char_spec(int index)
+__weak uchar env_get_char_spec(int index)
 {
 	return *((uchar *)(gd->env_addr + index));
 }
-uchar env_get_char_spec(int)
-	__attribute__((weak, alias("__env_get_char_spec")));
 
 static uchar env_get_char_init(int index)
 {