Update edk2 headers to stable202005

We use these to compile libefivar. The particular motivation for this update is
the inclusion of the RISC-V machine definitions that allow us to build the
library on the platform. This support could easily have been submitted as a
small local diff, but the timing of the release coincided with this work, and
it has been over 3 years since these sources were initially imported.

Note that this comes with a license change from regular BSD 2-clause to the
BSD+Patent license. This has been approved by core@ for this particular
project [1].

As with the original import, we retain only the subset of headers that we
actually need to build libefivar. I adapted imp@'s process slightly for this
update:

1. Generate list of the headers needed to build cp -r ../vendor/edk2/dist/MdePkg/Include sys/contrib/edk2 cd lib/libefivar make pushd make -V .OBJDIR cat .depend*.o | grep sys/contrib | cut -d' ' -f 3 | sort -u | sed -e 's=/full/path/sys/contrib/edk2/==' > /tmp/xxx popd
2. Merge the needed files cd ../../sys/contrib/edk2 svn revert -R . for i in cat /tmp/xxx; do svn merge -c VendorRevision svn+ssh://repo.freebsd.org/base/vendor/edk2/dist/MdePkg/$i $i done svn merge -c VendorRevision svn+ssh://repo.freebsd.org/base/vendor/edk2/dist/MdePkg/MdePkg.dec MdePkg.dec

[1] https://www.freebsd.org/internal/software-license.html