x86/cpu: Remove unneeded 64-bit dependency in arch_enter_from_user_mode()

The check for 64-bit mode when testing X86_FEATURE_XENPV isn't needed,
as Xen PV guests are no longer supported in 32-bit mode, see

  a13f2ef1 ("x86/xen: remove 32-bit Xen PV guest support").

While at it switch from boot_cpu_has() to cpu_feature_enabled().
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20221104072701.20283-3-jgross@suse.com

arch/x86/include/asm/entry-common.h

@@ -24,8 +24,8 @@ static __always_inline void arch_enter_from_user_mode(struct pt_regs *regs)
 		/*
 		 * For !SMAP hardware we patch out CLAC on entry.
 		 */
-		if (boot_cpu_has(X86_FEATURE_SMAP) ||
-		    (IS_ENABLED(CONFIG_64BIT) && boot_cpu_has(X86_FEATURE_XENPV)))
+		if (cpu_feature_enabled(X86_FEATURE_SMAP) ||
+		    cpu_feature_enabled(X86_FEATURE_XENPV))
 			mask |= X86_EFLAGS_AC;
 
 		WARN_ON_ONCE(flags & mask);