lkdtm: split usercopy tests to separate file

This splits the USERCOPY_* tests into the new lkdtm_usercopy.c file to
help separate things better for readability.

Signed-off-by: Kees Cook <keescook@chromium.org>
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 7d45ed4..e6b2778 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -60,6 +60,7 @@
 
 lkdtm-$(CONFIG_LKDTM)		+= lkdtm_core.o
 lkdtm-$(CONFIG_LKDTM)		+= lkdtm_rodata_objcopy.o
+lkdtm-$(CONFIG_LKDTM)		+= lkdtm_usercopy.o
 
 OBJCOPYFLAGS :=
 OBJCOPYFLAGS_lkdtm_rodata_objcopy.o := \