drm/amdgpu: fix send ras disable cmd when asic not support ras

    cause:
	It is necessary to send ras disable command to ras-ta during gfx
	block ras later init, because the ras capability is disable read
	from vbios for vega20 gaming, but the ras context is released
	during ras init process, this will cause send ras disable command
	to ras-to failed.
    how:
	Delay releasing ras context, the ras context
	will be released after gfx block later init done.

Changed from V1:
    move release_ras_context into ras_resume

Changed from V2:
    check BIT(UMC) is more reasonable before access eeprom table

Signed-off-by: Stanley.Yang <Stanley.Yang@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>