[libomptarget] Refactor DeviceRTL prior to AMDGPU bringup

Subset of D111993. Fix typos, rename read to load.

Reviewed By: tianshilei1992

Differential Revision: https://reviews.llvm.org/D111999

GitOrigin-RevId: 7272982e1dfe89d492de4aac3e23d9cdcb1198fa
5 files changed