fs/ntfs3: Don't use uni1 uninitialized in ntfs_d_compare()

Clang warns:

  fs/ntfs3/namei.c:445:7: error: variable 'uni1' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
                  if (toupper(c1) != toupper(c2)) {
                      ^~~~~~~~~~~~~~~~~~~~~~~~~~
  ./include/linux/ctype.h:64:20: note: expanded from macro 'toupper'
  #define toupper(c) __toupper(c)
                    ^
  fs/ntfs3/namei.c:487:12: note: uninitialized use occurs here
          __putname(uni1);
                    ^~~~
  ./include/linux/fs.h:2789:65: note: expanded from macro '__putname'
  #define __putname(name)         kmem_cache_free(names_cachep, (void *)(name))
                                                                        ^~~~
  fs/ntfs3/namei.c:445:3: note: remove the 'if' if its condition is always false
                  if (toupper(c1) != toupper(c2)) {
                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  fs/ntfs3/namei.c:434:7: error: variable 'uni1' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
                  if (!lm--) {
                      ^~~~~
  fs/ntfs3/namei.c:487:12: note: uninitialized use occurs here
          __putname(uni1);
                    ^~~~
  ./include/linux/fs.h:2789:65: note: expanded from macro '__putname'
  #define __putname(name)         kmem_cache_free(names_cachep, (void *)(name))
                                                                        ^~~~
  fs/ntfs3/namei.c:434:3: note: remove the 'if' if its condition is always false
                  if (!lm--) {
                  ^~~~~~~~~~~~
  fs/ntfs3/namei.c:430:22: note: initialize the variable 'uni1' to silence this warning
          struct cpu_str *uni1, *uni2;
                              ^
                              = NULL
  2 errors generated.

There is no point in calling __putname() in these particular error
paths, as there has been no corresponding __getname() call yet. Just
return directly in these blocks to clear up the warning.

Fixes: a3a956c7 ("fs/ntfs3: Add option "nocase"")
Link: https://github.com/ClangBuiltLinux/linux/issues/1729


Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>