Update vdpauwidget.cpp

There was an issue with the datatypes
As an Example:

With int:
MIXER TEMPORAL (1920x1080): -219418 fields/s
MIXER TEMPORAL + IVTC (1920x1080): -213874 fields/s
MIXER TEMPORAL + SKIP_CHROMA (1920x1080): -209002 fields/s
MIXER TEMPORAL_SPATIAL (1920x1080): -209450 fields/s
MIXER TEMPORAL_SPATIAL + IVTC (1920x1080): -208842 fields/s
MIXER TEMPORAL_SPATIAL + SKIP_CHROMA (1920x1080): -210538 fields/s
MIXER TEMPORAL_SPATIAL (720x576 video to 1920x1080 display): -194210 fields/s

With long:
MIXER TEMPORAL (1920x1080): 89 fields/s
MIXER TEMPORAL + IVTC (1920x1080): 89 fields/s
MIXER TEMPORAL + SKIP_CHROMA (1920x1080): 89 fields/s
MIXER TEMPORAL_SPATIAL (1920x1080): 90 fields/s
MIXER TEMPORAL_SPATIAL + IVTC (1920x1080): 90 fields/s
MIXER TEMPORAL_SPATIAL + SKIP_CHROMA (1920x1080): 90 fields/s
MIXER TEMPORAL_SPATIAL (720x576 video to 1920x1080 display): 90 fields/s