Some configurations won't allow ueventd to have CAP_NET_ADMIN, so the
new default size of 16M is not possible for those. Those
configurations also won't need such a large buffer size, so this
change allows devices to customize the SO_RCVBUF(FORCE) size for the
uevent socket.
This is done by adding the line 'uevent_socket_rcvbuf_size <size>' to
your device's ueventd.rc file. <size> is specified as a byte count,
for example '16M' is 16MiB.
The last parsed uevent_socket_rcvbuf_size line is the one that is
used.
Bug: 120485624
Test: boot sailfish
Test: ueventd unit tests
Change-Id: If8123b92ca8a9b089ad50318caada2f21bc94707