vmm: amd: Remove manual instruction encodings

[adam_fenn.io]

Summary

Remove manual encodings for VMLOAD, VMRUN, and VMSAVE now that
they are no longer necessary.

Test Plan

Confirmed no functional change via checksum of .text before and after
change:

$ ls vmm.ko-*
vmm.ko-after    vmm.ko-before
$ objcopy --only-section='.text' --strip-all vmm.ko-after{,.text}
$ objcopy --only-section='.text' --strip-all vmm.ko-before{,.text}
$ ls vmm.ko-*
vmm.ko-after            vmm.ko-after.text       vmm.ko-before           vmm.ko-before.text
$ md5 vmm.ko-*
MD5 (vmm.ko-after) = 785bec65665cce3d744cce1edc163549
MD5 (vmm.ko-after.text) = 39135dd797550b6443c6803eb7cd141a
MD5 (vmm.ko-before) = 3867c57954b9edaf246e355d0c8e789b
MD5 (vmm.ko-before.text) = 39135dd797550b6443c6803eb7cd141a