drm/amdgpu: validate user queue size constraints

drm/amdgpu: validate user queue size constraints

Add validation to ensure user queue sizes meet hardware requirements:
- Size must be a power of two for efficient ring buffer wrapping
- Size must be at least AMDGPU_GPU_PAGE_SIZE to prevent undersized allocations

This prevents invalid configurations that could lead to GPU faults or
unexpected behavior.

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Jesse Zhang <jesse.zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>