driver: ppm_ringbuffer.h: fix up structure types

This fixes the rest of the fields in the exported structure to use the
correct kernel types.
driver: fix up more types

This fixes up the types used in val_to_ring()
driver/ppm_fillers.c: removed unneeded {}

This fixes up all of the:
  WARNING: braces {} are not necessary for single statement blocks
issues in this file.
Merge pull request #70 from gregkh/kernel_code_style

More kernel coding style fixups