Staging: hv: fix various coding style issues in RingBuffer.c

This is a patch to the RingBuffer.c file that corrects various coding style
warnings and errors found by checkpatch.pl

[ The real solution here is to get rid of this file entirely, and use the
kernel's internal ring buffer api, but until then, make these changes so as to
make checkpatch.pl happy, and keep others from continuously sending this type
of patch. - gkh]

Signed-off-by: Craig Bartlett <c-bartlett@hotmail.co.uk>
Cc: Bill Pemberton <wfp5p@virginia.edu>
Cc: Nicolas Palix <npalix@diku.dk>
Cc: Hank Janssen <hjanssen@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>