x86/entry/64: Remove error code clearing from #DB and #MCE ASM stub

The C entry points do not expect an error code.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505135314.992621707@linutronix.de

arch/x86/entry/entry_64.S

@@ -642,7 +642,6 @@ SYM_CODE_START(\asmsym)
 	.endif
 
 	movq	%rsp, %rdi		/* pt_regs pointer */
-	xorl	%esi, %esi		/* Clear the error code */
 
 	.if \vector == X86_TRAP_DB
 		subq	$DB_STACK_OFFSET, CPU_TSS_IST(IST_INDEX_DB)