[AMDGPU] Disable forceful inline of non-kernel functions which use LDS.

Now since LDS uses within non-kernel functions are being handled in the
pass - LowerModuleLDS, we *NO* need to *forcefully* inline non-kernel
functions just because they use LDS. Do forceful inlining only when the
pass - LowerModuleLDS is not enabled. It is enabled by default.

Reviewed By: JonChesterfield

Differential Revision: https://reviews.llvm.org/D100481