devproc: check for #mnt instead of #M

We missed this when changing the names of all of the devices.  All 9ns
device names are strings, not single characters.

Signed-off-by: Barret Rhoden <brho@cs.berkeley.edu>

kern/drivers/dev/proc.c

diff --git a/kern/drivers/dev/proc.c b/kern/drivers/dev/proc.c
index c6479fc..c8051d0 100644
--- a/kern/drivers/dev/proc.c
+++ b/kern/drivers/dev/proc.c
@@ -1018,7 +1018,7 @@
 				return i;
 			}
 			int2flag(mw->cm->mflag, flag);
-			if (strcmp(mw->cm->to->name->s, "#M") == 0) {
+			if (strcmp(mw->cm->to->name->s, "#mnt") == 0) {
 				srv = srvname(mw->cm->to->mchan);
 				i = snprintf(va, n, "mount %s %s %s %s\n", flag,
 							 srv == NULL ? mw->cm->to->mchan->name->s : srv,