package/python-flit-core: set license path

When generating legal info with a configuration enabling a package which uses
flit as setup type, we get a warning about python-flit-core license:
WARNING: python-flit-core-3.8.0: cannot save license (HOST_PYTHON_FLIT_CORE_LICENSE_FILES not defined)

Add missing variable to point to python-flit-core license file

Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>
[Peter: add sha256sum to .hash file]
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/python-flit-core/python-flit-core.hash

@@ -1,3 +1,5 @@
 # md5, sha256 from https://pypi.org/pypi/flit_core/json
 md5  7c41da13273f7787709a24f74e0f5a99  flit_core-3.8.0.tar.gz
 sha256  b305b30c99526df5e63d6022dd2310a0a941a187bd3884f4c8ef0418df6c39f3  flit_core-3.8.0.tar.gz
+# Locally computed
+sha256  35b4f1dec512e617077fd6980dbb43ef8c2887adc5d0185edb4c04da175dd816  LICENSE

package/python-flit-core/python-flit-core.mk

@@ -8,6 +8,7 @@ PYTHON_FLIT_CORE_VERSION = 3.8.0
 PYTHON_FLIT_CORE_SOURCE = flit_core-$(PYTHON_FLIT_CORE_VERSION).tar.gz
 PYTHON_FLIT_CORE_SITE = https://files.pythonhosted.org/packages/10/e5/be08751d07b30889af130cec20955c987a74380a10058e6e8856e4010afc
 PYTHON_FLIT_CORE_LICENSE = BSD-3-Clause
+PYTHON_FLIT_CORE_LICENSE_FILES = LICENSE
 PYTHON_FLIT_CORE_SETUP_TYPE = flit-bootstrap
 
 # Use flit built in bootstrap_install for installing host-python-flit-core.