nfit: move to nfit/ sub-directory

With the arrival of x86-machine-check support the nfit driver will add a
(conditionally-compiled) source file.  Prepare for this by moving all
nfit source to drivers/acpi/nfit/.  This is pure code movement, no
functional changes.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/tools/testing/nvdimm/Kbuild b/tools/testing/nvdimm/Kbuild
index 62d5ac3..0dca8ff 100644
--- a/tools/testing/nvdimm/Kbuild
+++ b/tools/testing/nvdimm/Kbuild
@@ -16,7 +16,7 @@
 
 DRIVERS := ../../../drivers
 NVDIMM_SRC := $(DRIVERS)/nvdimm
-ACPI_SRC := $(DRIVERS)/acpi
+ACPI_SRC := $(DRIVERS)/acpi/nfit
 DAX_SRC := $(DRIVERS)/dax
 ccflags-y := -I$(src)/$(NVDIMM_SRC)/
 
@@ -29,7 +29,7 @@
 obj-$(CONFIG_DEV_DAX) += dax.o
 obj-$(CONFIG_DEV_DAX_PMEM) += dax_pmem.o
 
-nfit-y := $(ACPI_SRC)/nfit.o
+nfit-y := $(ACPI_SRC)/core.o
 nfit-y += config_check.o
 
 nd_pmem-y := $(NVDIMM_SRC)/pmem.o