gpu: pvr: pdump: stop depending on dbgdrvif.h

gpu: pvr: pdump: stop depending on dbgdrvif.h

Stop including dbgdrvif.h in pdump.c and add empty skeleton for
former dbgdrv functionality.

So replace the pointer with callbacks with locally defined, mostly
empty, functions. Provide stripped down struct DBG_STREAM and define
the still referenced flags inside pdump.c.

Only functional change is that the dbgdrv module and the pdump
userspace utility are now completely useless.

Signed-off-by: Luc Verhaegen <Luc.Verhaegen@basyskom.de>
Signed-off-by: Imre Deak <imre.deak@nokia.com>