Unify mmap error messages

Corresponding to flashrom svn r112 and coreboot v2 svn r2690.

Signed-off-by: Stefan Reinauer <stepan@coresystems.de>
Acked-by: Stefan Reinauer <stepan@coresystems.de>
diff --git a/sharplhf00l04.c b/sharplhf00l04.c
index fd3a714..a4d086e 100644
--- a/sharplhf00l04.c
+++ b/sharplhf00l04.c
@@ -82,7 +82,7 @@
 			    fd_mem, (off_t) (0 - 0x400000 - size));
 		if (registers == MAP_FAILED) {
 			// it's this part but we can't map it ...
-			perror("Error MMAP /dev/mem");
+			perror("Can't mmap memory using " MEM_DEV);
 			exit(1);
 		}