This reverts commit 118a57045b.
Reason for revert: Fails on Visual Studio builds:
vpxmdd.lib(vpx_ports_emms_mmx.obj) : error LNK2019: unresolved
external symbol _m_empty referenced in function
vpx_clear_system_state
Original change's description:
> use intrinsics for 'emms'
>
> BUG=webm:1500
>
> Change-Id: I3235d8c2abc01dd3a35e14c5cbcfe20283ff8fb2
Change-Id: Ia9c40bc103c57cced83353249c55218eaf2f0b0c