[PPC64][VSX] Add short, char, and bool data type for vec_vsx_ld and vec_vsx_st intrinsics

Issue: https://llvm.org/bugs/show_bug.cgi?id=26720

Fix compile error when building ffmpeg for PowerPC64LE because of some
vec_vsx_ld/vec_vsx_st intrinsics are not supported by current clang.

New added intrinsics:

(vector) {signed|unsigned} {short|char} vec_vsx_ld: (total: 8)
bool vec_vsx_ld: (total: 1)
(vector) {signed|unsigned} {short|char} vec_vsx_st: (total: 8)
bool vec_vsx_st: (total: 1)
Total: 18 intrinsics

Phabricator: http://reviews.llvm.org/D17637
llvm-svn: 262359