OvmfPkg: Work around issue seen with kvm + grub2 (efi)

OvmfPkg: Work around issue seen with kvm + grub2 (efi)

When OVMF is run with kvm and grub2 (efi), an exception
occurs when mmx/sse registers are accessed.

As a work around, this change eliminates firmware usage
of these register types.

First, only the BaseMemoryLib implementation
MdePkg/Library/BaseMemoryLibRepStr/BaseMemoryLibRepStr.inf
is used.

Second, the GCC compiler is passes the additional
'-mno-mmx -mno-sse' parameters.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@11218 6f19259b-4bc3-4df7-8a09-765794883524