x86: fix typo in step.c

TIF_DEBUGCTLMSR has no meaning in the actual MSR...

Signed-off-by: Jan Beulich <[e-mail]>
Signed-off-by: Ingo Molnar <[e-mail]>

arch/x86/kernel/step.c

···
 				  child->thread.debugctlmsr | DEBUGCTLMSR_BTF);
 	} else {
 	    write_debugctlmsr(child,
-			      child->thread.debugctlmsr & ~TIF_DEBUGCTLMSR);
+			      child->thread.debugctlmsr & ~DEBUGCTLMSR_BTF);
 
 	    if (!child->thread.debugctlmsr)
 		    clear_tsk_thread_flag(child, TIF_DEBUGCTLMSR);
···
 	 * Make sure block stepping (BTF) is disabled.
 	 */
 	write_debugctlmsr(child,
-			  child->thread.debugctlmsr & ~TIF_DEBUGCTLMSR);
+			  child->thread.debugctlmsr & ~DEBUGCTLMSR_BTF);
 
 	if (!child->thread.debugctlmsr)
 		clear_tsk_thread_flag(child, TIF_DEBUGCTLMSR);