fix header install

The meson changes moved where header files were installed, causing
other projects that depend on the headers being present to fail to
build.

This installs the header files like they were before.

Tested: can build the intel-ipmi-oem code again

Change-Id: Icd826b2f264603b8f7e32f7d7eaeb2c319b381cb
Signed-off-by: Vernon Mauery <vernon.mauery@linux.intel.com>
1 file changed