x86/asm/entry/64: Always set up SYSENTER MSRs

x86/asm/entry/64: Always set up SYSENTER MSRs

On CONFIG_IA32_EMULATION=y kernels we set up
MSR_IA32_SYSENTER_CS/ESP/EIP, but on !CONFIG_IA32_EMULATION
kernels we leave them unchanged.

Clear them to make sure the instruction is disabled properly.

SYSCALL is set up properly in both cases.

Acked-by: Denys Vlasenko <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Will Drewry <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>