drm/v3d: Create a new V3D parameter for the maximum number of perfcnt

The maximum number of performance counters can change from version to
version and it's important for userspace to know this value, as it needs
to use the counters for performance queries. Therefore, expose the
maximum number of performance counters to userspace as a parameter.

Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240512222655.2792754-4-mcanal@igalia.com