ntfs: Use return instead of goto in ntfs_mapping_pairs_decompress()

ntfs: Use return instead of goto in ntfs_mapping_pairs_decompress()

Clang warns (or errors with CONFIG_WERROR=y / W=e):

  fs/ntfs/runlist.c:755:6: error: variable 'rl' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
    755 |         if (overflows_type(lowest_vcn, vcn)) {
        |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  ...
  fs/ntfs/runlist.c:971:9: note: uninitialized use occurs here
    971 |         kvfree(rl);
        |                ^~
  ...

rl has not been allocated at this point so the 'goto err_out' should
really just be a return of the error pointer -EIO.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>