gtest: fix installation in multilib

The installation and pkgconfig patches have to be reworked to consider
the install directories from OE.

Signed-off-by: Frederico Cadete <frederico.cadete@awtce.be>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
(cherry picked from commit 377d67aa7cb902d4a512c3489482fb876b1ec4cd)
Signed-off-by: Armin Kuster <akuster808@gmail.com>