Fix minor spelling typo in the mke2fs man page.

diff --git a/misc/mke2fs.8.in b/misc/mke2fs.8.in
index 52085f9..1b1bb67 100644
--- a/misc/mke2fs.8.in
+++ b/misc/mke2fs.8.in
@@ -305,7 +305,7 @@
 .B \-M
 Set the last mounted directory for the filesystem.  This might be useful 
 for the sake of utilities that key off of the last mounted directory to 
-determine where the filesytem should be mounted.
+determine where the filesystem should be mounted.
 .TP
 .B \-n
 causes mke2fs to not actually create a filesystem, but display what it