sdm710-common: Add panel properties

Fingerprint HAL looks for sys.panel.{color,display,touch_vendor,vendor}
properties:
E [GF_HAL][XiaoMiSensor]: [init] Failed getting sys.panel.display property
E [GF_HAL][ExtModuleCreator]: Failed to getprop sys.panel.touch_vendor
E [GF_HAL][ExtModuleCreator]: Failed to getprop sys.panel.Vendor

On stock ROM these properties are set by init.panel_info.sh script
that translates lockdown-info values from touchscreen drivers.
After investigation of lockdown info from pyxis, vela, grus and xmsirius
all these properties' values are the same: color is BLACK and panel
and display vendor are SDC (Samsung Display Corp).

Add these properties and label them so the fingerprint HAL can access
them. After testing on Pyxis it looks that FP operations are more
reliable.

Change-Id: I9bcc471265ef364318bada305c2ea25110127606

sepolicy/vendor/property_contexts

@@ -27,6 +27,7 @@ persist.vendor.fpc.                             u:object_r:vendor_fp_prop:s0
 persist.vendor.sys.fp.                          u:object_r:vendor_fp_prop:s0
 ro.boot.fpsensor                                u:object_r:vendor_fp_prop:s0
 ro.hardware.fp                                  u:object_r:vendor_fp_prop:s0
+sys.panel.                                      u:object_r:vendor_fp_prop:s0
 vendor.fps_hal.                                 u:object_r:vendor_fp_prop:s0
 
 # MIUI specific

system.prop

@@ -66,6 +66,11 @@ media.settings.xml=/vendor/etc/media_profiles_vendor.xml
 # Netflix custom property
 ro.netflix.bsp_rev=Q670-14477-1
 
+# Panel
+sys.panel.color=BLACK
+sys.panel.display=SDC
+sys.panel.vendor=SDC
+
 # RCS
 persist.rcs.supported=0