[HIP] Fix amdgcn builtin for long type

Currently some amdgcn builtins are defined with long int type,
which causes invalid IR on Windows since long int is 32 bit
on Windows whereas these builtins have 64 bit arguments.

long long int type cannot be used since it is 128 bit in OpenCL.

This patch uses 64 bit int type instead of long int to define 64 bit int
arguments or return for amdgcn builtins.

Reviewed by: Artem Belevich

Differential Revision: https://reviews.llvm.org/D103563