constify (a few) parameters in flashrom.c where possible

Signed-off-by: Stefan Tauner <stefan.tauner@student.tuwien.ac.at>
Acked-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>

git-svn-id: svn://coreboot.org/flashrom/trunk@1354 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1
diff --git a/programmer.h b/programmer.h
index ce0ffa1..cd82dcb 100644
--- a/programmer.h
+++ b/programmer.h
@@ -505,7 +505,7 @@
 extern unsigned long flashbase;
 void check_chip_supported(const struct flashchip *flash);
 int check_max_decode(enum chipbustype buses, uint32_t size);
-char *extract_programmer_param(char *param_name);
+char *extract_programmer_param(const char *param_name);
 
 /* layout.c */
 int show_id(uint8_t *bios, int size, int force);