fm10k: TRIVIAL cleanup of extra spacing in function comment

The function comment for fm10k_iov_msg_msix_pf has an extra space in
a sentence, which is unnecessary.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>