x86_64: GenInlinedCas must use wide rl_src_offset under 64-bit targets

This patch fixes to use wide rl_src_offset for int and long types
under 64-bit targets, and fixes movzx8 and movsx8 to use r8_form
on the second register only.

Change-Id: Ib8c0756609100f9bc5c228f1eb391421416f3af6
Signed-off-by: Chao-ying Fu <chao-ying.fu@intel.com>