[ARM MVE] Remove accidental 64-bit vst2/vld2 intrinsics.

[simon_tatham]

Summary

ACLE defines no such intrinsic as vst2q_u64, and the MVE instruction
set has no corresponding instruction. But I had accidentally added
them to the fledgling <arm_mve.h> anyway, and if you used them, you'd
get a compiler crash.

[dmgreen]

LGTM.

I was trying to think of a way to test this, but couldn't come up with anything sensible.

clang/include/clang/Basic/arm_mve.td

 // Refer to comments in arm_mve_defs.td for the infrastructure used in
 // here, and to MveEmitter.cpp for how those are used in turn to
 // generate code.
 //
 //===----------------------------------------------------------------------===//
 
 include "arm_mve_defs.td"
 
-let params = T.All in
+let params = T.Usual in
 foreach n = [ 2, 4 ] in {
   def "vst"#n#"q": Intrinsic<Void, (args Ptr<Scalar>, MultiVector<n>),
                              (CustomCodegen<"VST24"> n:$NumVectors,
                               "Intrinsic::arm_mve_vst"#n#"q":$IRIntr)>;
   def "vld"#n#"q": Intrinsic<MultiVector<n>, (args CPtr<Scalar>),
                              (CustomCodegen<"VLD24"> n:$NumVectors,
                               "Intrinsic::arm_mve_vld"#n#"q":$IRIntr)>;
 }