package/efl/libelementary: bump to version 1.15.2

Use the newly added libefl package wich provide a new version
of libeina, libevas, libecore and libedje.

Update the upstream url and add a hash file.

We need to add a host package to provide elm_prefs_cc the
host machine to cross-compile correctly libelementary
for the target. Otherwise, elm_prefs_cc for the
target is used on the host machine.

Since eet, eolian_gen and eldbus_codegen are installed in
HOST_DIR by host-efl package, help configure script to find
them.

Explicitly disable doxygen and elementary-test.

[Thomas: add explicit select BR2_PACKAGE_LIBEFL.]

Signed-off-by: Romain Naour <romain.naour@openwide.fr>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>