drm/amdgpu/vcn: Remove unnecessary check

The function amdgpu_vcn_sysfs_reset_mask_init already returns 0, which
makes the check of the result unnecessary in the vcn_v4_0_3_sw_init().
Just return the amdgpu_vcn_sysfs_reset_mask_init directly.

Signed-off-by: Rodrigo Siqueira <siqueira@igalia.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>