efi_loader: rename Unicode collation protocol 2 variables

Rename variables to make it clear they refer to the Unicode collation
protocol identified by the EFI_UNICODE_PROTOCOL2_GUID.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
index f3d6773..01769ea 100644
--- a/lib/efi_loader/Makefile
+++ b/lib/efi_loader/Makefile
@@ -30,7 +30,7 @@
 obj-y += efi_root_node.o
 obj-y += efi_runtime.o
 obj-y += efi_setup.o
-obj-$(CONFIG_EFI_UNICODE_COLLATION_PROTOCOL) += efi_unicode_collation.o
+obj-$(CONFIG_EFI_UNICODE_COLLATION_PROTOCOL2) += efi_unicode_collation.o
 obj-y += efi_variable.o
 obj-y += efi_watchdog.o
 obj-$(CONFIG_LCD) += efi_gop.o