scripts/checkpatch.pl: Detect superfluous semicolon in C code

scripts/checkpatch.pl: Detect superfluous semicolon in C code

Display error when a commit contains superfluous semicolon:

  $ git show 6663a0a3376 | scripts/checkpatch.pl -q -
  ERROR: superfluous trailing semicolon
  #276: FILE: block/io_uring.c:186:
  +                ret = -ENOSPC;;
  total: 1 errors, 1 warnings, 485 lines checked

Reported-by: Luc Michel <[email protected]>
Signed-off-by: Philippe Mathieu-Daudé <[email protected]>
Acked-by: Paolo Bonzini <[email protected]>
Reviewed-by: Dr. David Alan Gilbert <[email protected]>
Reviewed-by: Juan Quintela <[email protected]>
Reviewed-by: Luc Michel <[email protected]>
Message-Id: <20200218094402[email protected]>
Signed-off-by: Laurent Vivier <[email protected]>