uml: reconst a parameter

The previous const-ing patch consted a string which shouldn't have
been, and I didn't notice the gcc warning.

ubd_setup can't take a const char * because its address is assigned to
something which expects a char *arg.  Many setups modify the string
they are given, they can't be const.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/um/drivers/ubd_kern.c

@@ -444,7 +444,7 @@ __uml_help(ubd_setup,
 "    cluster filesystem and inappropriate at almost all other times.\n\n"
 );
 
-static int udb_setup(const char *str)
+static int udb_setup(char *str)
 {
 	printk("udb%s specified on command line is almost certainly a ubd -> "
 	       "udb TYPO\n", str);