- Copy stable/10@296371 to releng/10.3 in preparation for 10.3-RC1
builds.
- Update newvers.sh to reflect RC1.
- Update __FreeBSD_version to reflect 10.3.
- Update default pkg(8) configuration to use the quarterly branch.

Approved by: re (implicit)

MFC r270945:

Rename OF_xref_phandle() to OF_node_from_xref() and add a new function
that provides the inverse translation, OF_xref_from_node().

MFC r261982, r261987, r262123, r262244, r262278, r262280, r262353, r262354,
r262355, r262419,

Add Vybrid driver for Synchronous Audio Interface (SAI).

Decrease SAI buffer size. Handle eDMA interrupt on running channel only.

Give the physmem fdt helper routines static linkage since no global
definition of them is provided anywhere.

Add imx6 early printf support, wrapped in #if 0 because it's rarely needed.

Add basic cpu frequency control and temperature monitoring to imx6_anatop.

Add the FREEBSD_BOOT_LOADER option so that a loaded DTB passed in from
ubldr will actually get used.

Create a generic IMX6 kernel config, then fix it to have an ident line.

Don't force imx6 bootverbose on anymore, it can be set from ubldr now.

Add driver for Synchronous Audio Interface (SAI).

SAI supports full-duplex serial interfaces with frame
synchronization such as I2S, AC97, TDM, and codec/DSP
interfaces.