sepolicy: Add sepolicy for hal_memtrack to read sysfs_kgsl_proc

Add sepolicy for hal_memtrack_default to read kgsl memory.

avc: denied { read } for comm="memtrack@1.0-se"
name="gpumem_mapped"dev="sysfs" ino=82422
scontext=u:r:hal_memtrack_default:s0
tcontext=u:object_r:sysfs:s0 tclass=file permissive=0.

CRs-Fixed: 2421195

Change-Id: I254df836754b5ebc09f44f7053edf85867a963a5