i965: Add 2x MSAA support to Broadwell fast clear code.

According to the cited documentation section (but in the newer docs),
x_scaledown is the same for 2x and 4x MSAA.

+47 piglits.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=83081
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Cc: "10.3" <mesa-stable@lists.freedesktop.org>
(cherry picked from commit e34a363a781a24b2cf6930c4d37f781ffec8a19a)
i965/vec4: Update register coalescing test.

In commit 04895f5c I added support for reswizzling writemasks. This test
was checking that we didn't support this.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=82881
(cherry picked from commit 8b5ac1df17608e0d0d5ce412988ee8de97f61405)
mesa: fix make tarballs

Current method of generating distribution tar-balls involves manually
invoking make + target name in the appropriate places. This temporary
solution is used until we get 'make dist' working.

Currently it does not work, as in order to have the target (which is
also a filename) available in the final Makefile we need to add a PHONY
target + use the correct target name.

Cc: "10.2 10.3" <mesa-stable@lists.freedesktop.org>
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
(cherry picked from commit 88cbe3908f0ea08228a5ffb1808f98b6906c4416)
Increment version to 10.3.0-rc2

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>