KVM: VMX: remove functions that enable msr intercepts

All intercepts are enabled at the beginning, so they can only be used if
we disabled an intercept that we wanted to have enabled.
This was done for TMCCT to simplify a loop that disables all x2APIC MSR
intercepts, but just keeping TMCCT enabled yields better results.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>