efi/libstub/x86: simplify efi_is_native()

CONFIG_EFI_MIXED depends on CONFIG_X86_64=y.
There is no need to check CONFIG_X86_64 again.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Link: https://lore.kernel.org/r/20201003060356.4913-1-xypron.glpk@gmx.deSigned-off-by: Ard Biesheuvel <ardb@kernel.org>

arch/x86/include/asm/efi.h

@@ -213,8 +213,6 @@ static inline bool efi_is_64bit(void)
 
 static inline bool efi_is_native(void)
 {
-	if (!IS_ENABLED(CONFIG_X86_64))
-		return true;
 	return efi_is_64bit();
 }