of/unittest: Rename selftest.c to unittest.c

This is unit testing code. It should use that name because it makes more
sense than 'selftest'. Rename the files to match and rename the config
variable.

Signed-off-by: Grant Likely <grant.likely@linaro.org>
diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index ca9209c..d90553f 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -6,8 +6,8 @@
 obj-$(CONFIG_OF_ADDRESS)  += address.o
 obj-$(CONFIG_OF_IRQ)    += irq.o
 obj-$(CONFIG_OF_NET)	+= of_net.o
-obj-$(CONFIG_OF_SELFTEST) += of_selftest.o
-of_selftest-objs := selftest.o testcase-data/testcases.dtb.o
+obj-$(CONFIG_OF_UNITTEST) += of_unittest.o
+of_unittest-objs := unittest.o unittest-data/testcases.dtb.o
 obj-$(CONFIG_OF_MDIO)	+= of_mdio.o
 obj-$(CONFIG_OF_PCI)	+= of_pci.o
 obj-$(CONFIG_OF_PCI_IRQ)  += of_pci_irq.o