drm/amdkfd: Fix bug in call to init_pipelines()

This patch fixes a bug where the first_pipe index passed into init_pipelines()
was a #define instead of the value that is passed into amdkfd by radeon

Signed-off-by: Oded Gabbay <oded.gabbay@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Jammy Zhou <Jammy.Zhou@amd.com>