efi_loader: EFI_VARIABLE_READ_ONLY should be 32bit

GetVariable() and SetVariable() only accept a 32bit value for attributes.
It makes not sense to define EFI_VARIABLE_READ_ONLY as unsigned long.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
diff --git a/include/efi_variable.h b/include/efi_variable.h
index 805e6c5..42a2b7c 100644
--- a/include/efi_variable.h
+++ b/include/efi_variable.h
@@ -8,7 +8,7 @@
 
 #include <linux/bitops.h>
 
-#define EFI_VARIABLE_READ_ONLY BIT(31)
+#define EFI_VARIABLE_READ_ONLY 0x80000000
 
 enum efi_auth_var_type {
 	EFI_AUTH_VAR_NONE = 0,