Opaque pointers: Update memory instructions in PatchBufferOp (#1917)
Opaque pointers: Update memory instructions in PatchBufferOp (#1917)

Since MemCpy and MemSet instructions are operating on bytes then
we can assume that pointee type is int8Ty.
GPUOpen-Drivers/llpc,GPUOpen-Drivers/llpc,GPUOpen-Drivers/llpc,GPUOpen-Drivers/llpc,GPUOpen-Drivers/llpc