/usr should not be hardcoded, as otherwise this will cause a double
prefix during installation.
The correct prefix is already being handled by CMAKE_INSTALL_PREFIX.
Example:
>>> /usr/usr/bin/ebuspicloader
>>> /usr/usr/bin/ebusctl
>>> /usr/usr/bin/ebusd
Signed-off-by: Conrad Kostecki <conikost@gentoo.org>
