uboot-imx

acpi: Clean IASL generated intermediate files

For boards that support ACPI, there are dsdt.aml, dsdt.asl.tmp and
dsdt.c in the board directory after a successful build. These are
intermediate files generated by IASL, and should be removed during
a 'make clean'.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>