efi_loader: use logical and in do_env_print_efi()

If we want to check if two booleans are true, we should use a logical
conjunction (&&) and not a bitwise and-operator (&).

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/cmd/nvedit_efi.c b/cmd/nvedit_efi.c
index 837e39e..6f69a84 100644
--- a/cmd/nvedit_efi.c
+++ b/cmd/nvedit_efi.c
@@ -298,7 +298,7 @@
 				return CMD_RET_USAGE;
 
 			/* -a already specified */
-			if (!default_guid & guid_any)
+			if (!default_guid && guid_any)
 				return CMD_RET_USAGE;
 
 			argc--;