[DOXYGEN] There was a request in the review D41507 to change the notation for...

[DOXYGEN] There was a request in the review D41507 to change the notation for hex numbers in doxygen documentation from <...>h to 0x<...>. Both of these notations were used in x86 intrinsics documentation. I promised to change them to 0x<...> for consistency.

Differential Revision: https://reviews.llvm.org/D41888

llvm-svn: 325312