ArmVirtPkg/PrePi ARM CLANG35: drop incompatible command line option

ArmVirtPkg/PrePi ARM CLANG35: drop incompatible command line option

Drop the -mno-movt command line option override, which is no longer
needed, and actually incompatible with versions of Clang before 3.6.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>