drm/i915/psr: Remove alpm from i915_psr

ALPM is a requirement and we don't need to keep it's cached, what
were done in commit 97c9de66
("drm/i915/psr: Fix ALPM cap check for PSR2") but the alpm was not
removed from i915_psr.
Reviewed-by: NDhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: NJosé Roberto de Souza <jose.souza@intel.com>
Signed-off-by: NDhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181003205031.32474-7-jose.souza@intel.com

drivers/gpu/drm/i915/i915_drv.h

@@ -634,7 +634,6 @@ struct i915_psr {
 	bool sink_psr2_support;
 	bool link_standby;
 	bool colorimetry_support;
-	bool alpm;
 	bool psr2_enabled;
 	u8 sink_sync_latency;
 	ktime_t last_entry_attempt;