common: Move old EEPROM functions into a new header

These functions do not use driver model but are still used. Move them to a
new eeprom.h header file.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/env/eeprom.c b/env/eeprom.c
index f0bdf2a..e8126cf 100644
--- a/env/eeprom.c
+++ b/env/eeprom.c
@@ -9,6 +9,7 @@
 
 #include <common.h>
 #include <command.h>
+#include <eeprom.h>
 #include <env.h>
 #include <env_internal.h>
 #include <linux/stddef.h>