drm/amd/pm: Limit jpeg rings as per max for jpeg_v_4_0_3

Since pmfw supports for smuv13_0_6 is limited to 8 jpeg rings per instance,
which is the max for jpeg_v_4_0_3. Limit it to same to avoid out
of bound access.

Fixes: 568199a5 ("drm/amd/pm: Limit to 8 jpeg rings per instance")
Signed-off-by: Asad Kamal <asad.kamal@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>