drm/amd: adjust whitespace for amdgpu_psp.h

Adjust the whitespace to be consistent with the rest of the
`struct psp_context` structure.
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>