media: saa6588: Remove dprintk macro and use v4l2_info()

media: saa6588: Remove dprintk macro and use v4l2_info()

The existing 'dprintk' macro used an unwrapped 'if' statement which was
flagged by checkpatch, but instead of wrapping it, the debug handling
can be simplified.

This patch removes the 'dprintk' macro entirely and replaces all its
usages with v4l2_info() helper. The unused 'PREFIX' macro is also
removed.

Signed-off-by: Shrikant Raskar <raskar.shree97@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>