x86/vmx: Drop spec_ctrl load in VMEntry path

This is not needed now that the VMEntry path is not responsible for loading
the guest's MSR_SPEC_CTRL value.

Fixes: 81f0eaadf8 ("x86/spec-ctrl: Fix NMI race condition with VT-x MSR_SPEC_CTRL handling")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

xen/arch/x86/hvm/vmx/entry.S

@@ -85,9 +85,6 @@ UNLIKELY_END(realmode)
         test %al, %al
         jz .Lvmx_vmentry_restart
 
-        mov VCPU_arch_msrs(%rbx), %rax
-        mov VCPUMSR_spec_ctrl_raw(%rax), %eax
-
         /* WARNING! `ret`, `call *`, `jmp *` not safe beyond this point. */
         /* SPEC_CTRL_EXIT_TO_VMX   Req: %rsp=regs/cpuinfo              Clob:    */
         ALTERNATIVE "", __stringify(verw CPUINFO_verw_sel(%rsp)), X86_FEATURE_SC_VERW_HVM