pixman: add patch to fix Microblaze build failure

The Microblaze build of pixman was failing due to FE_DIVBYZERO not
being implemented. It turns out that the usage of it, like fenv.h and
feenableexcept() is optional. So the patch simply adds a configure
check and disables the appropriate code (which is only use in the
tests anyway).

This commit also renames the existing patch to follow the patch naming
convention, and get a reliable ordering when applying patches.

Fixes:

  http://autobuild.buildroot.org/results/806/8064092cdbac85fbf4322429d29d5d11dc51860f/



Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>