ArmPkg/CompilerIntrinsicsLib: Make __aeabi_memcpy the same as memcpy

ArmPkg/CompilerIntrinsicsLib: Make __aeabi_memcpy the same as memcpy

This code also removed some redundant instructions.

__aeabi_memcpy doesn't require preservation of r0 (as memcpy does),
which could save a push, but the code has been left to keep things consistent.

The reason __aeabi_memcpy has been added to the .S file is so it will be available
to toolchains that use the GCC assembler but the full ARM EABI (i.e. current LLVM)

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Olivier Martin <olivier.martin@arm.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15124 6f19259b-4bc3-4df7-8a09-765794883524