Add pselect6 and eventfd2 syscalls
Includes following:
mediacodec: allow sendto and recvfrom syscalls
mediacodec: allow lseek syscall
mediaextractor: allow pread64 and readlinkat syscalls
mediacodec: allow getdents64, sysinfo and getcwd

Vendor extended policy files are separated from the aosp
and will now reside in /vendor

Change-Id: If59d04b36d744efb74209ae36e76dd16cb18f606
CRs-Fixed: 2027600