Cast _zzq_default to 64-bit before assigning it to a 64bit register

clang's integrated assembler is picky about pushing a 32-bit
variable into a 64-bit register. Cast it to the right size in
the asm statement.

Upstream bug: https://bugs.kde.org/show_bug.cgi?id=342008
Change-Id: Idd653bc5af5346bf1a22cabd429f1b5ec251f27a
Signed-off-by: Bernhard Rosenkränzer <Bernhard.Rosenkranzer@linaro.org>
Merge "Cast _zzq_default to 64-bit before assigning it to a 64bit register"