x86/vvmx: Drop the now-obsolete vmx_inst_check_privilege()

x86/vvmx: Drop the now-obsolete vmx_inst_check_privilege()

Now that nvmx_handle_vmx_insn() performs all VT-x instruction checks, there is
no need for redundant checking in vmx_inst_check_privilege().  Remove it, and
take out the vmxon_check boolean which was plumbed through decode_vmx_inst().

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Sergey Dyasli <sergey.dyasli@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>