env: Change env_match() to static and remove from header

This function was used by other parts of U-Boot in the past when
environment was read from underlying device one character at a time.

This is not the case anymore.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Simon Glass <sjg@chromium.org>

include/env.h

@@ -90,17 +90,6 @@ int env_init(void);
  */
 void env_relocate(void);
 
-/**
- * env_match() - Match a name / name=value pair
- *
- * This is used prior to relocation for finding envrionment variables
- *
- * @name: A simple 'name', or a 'name=value' pair.
- * @index: The environment index for a 'name2=value2' pair.
- * @return index for the value if the names match, else -1.
- */
-int env_match(unsigned char *name, int index);
-
 /**
  * env_get() - Look up the value of an environment variable
  *