x86/ioremap: Fix CONFIG_EFI=n build

In order to use efi_mem_type(), one needs CONFIG_EFI enabled. Otherwise
that function is undefined. Use IS_ENABLED() to check and avoid the
ifdeffery as the compiler optimizes away the following unreachable code
then.

Fixes: 985e537 ("x86/ioremap: Map EFI runtime services data as encrypted for SEV")
Reported-by: Randy Dunlap <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Tested-by: Randy Dunlap <[email protected]>
Cc: Tom Lendacky <[email protected]>
Cc: <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

Author: suryasaimadhu

arch/x86/mm/ioremap.c

@@ -115,6 +115,9 @@ static void __ioremap_check_other(resource_size_t addr, struct ioremap_desc *des
 	if (!sev_active())
 		return;
 
+	if (!IS_ENABLED(CONFIG_EFI))
+		return;
+
 	if (efi_mem_type(addr) == EFI_RUNTIME_SERVICES_DATA)
 		desc->flags |= IORES_MAP_ENCRYPTED;
 }