libpayload: add set_option() function

It allows to change CMOS values from payloads

Change-Id: I4872fc27476923adafe13504126235b92b30de85
Signed-off-by: Patrick Georgi <patrick.georgi@secunet.com>
Reviewed-on: http://review.coreboot.org/445
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

payloads/libpayload/include/libpayload.h

@@ -197,6 +197,7 @@ void video_console_set_cursor(unsigned int cursorx, unsigned int cursory);
 void fix_options_checksum(void);
 int get_option_from(struct cb_cmos_option_table *option_table, void *dest, char *name);
 int get_option(void *dest, char *name);
+int set_option(void *value, char *name);
 
 /**
  * @defgroup console Console functions