x86: xen: remove STACK_FRAME_NON_STANDARD from xen_cpuid

Since commit 4d65adfc ("x86: xen: insn: Decode Xen and KVM
emulate-prefix signature"), objtool is able to correctly parse the
prefixed instruction in xen_cpuid and emit correct orc unwind
information. Hence, marking the function as STACKFRAME_NON_STANDARD is
no longer needed.

This commit is basically a revert of commit 983bb6d2 ("x86/xen: Mark
xen_cpuid() stack frame as non-standard").
Signed-off-by: Maximilian Heyne <mheyne@amazon.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
CC: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://lore.kernel.org/r/20220517162425.100567-1-mheyne@amazon.deSigned-off-by: Juergen Gross <jgross@suse.com>

arch/x86/xen/enlighten_pv.c

@@ -30,7 +30,6 @@
 #include <linux/pci.h>
 #include <linux/gfp.h>
 #include <linux/edd.h>
-#include <linux/objtool.h>
 
 #include <xen/xen.h>
 #include <xen/events.h>
@@ -165,7 +164,6 @@ static void xen_cpuid(unsigned int *ax, unsigned int *bx,
 
 	*bx &= maskebx;
 }
-STACK_FRAME_NON_STANDARD(xen_cpuid); /* XEN_EMULATE_PREFIX */
 
 static bool __init xen_check_mwait(void)
 {