adt-installer: fix package installation issue

adt-installer: fix package installation issue

When the cross canadian toolchains are installed, for different
architectures, they might contain common files. This leads to
installation failures since the opkg, by default, does not overwrite
files. This issue happens, for example, for binutils packages (that
contain the same locale files) or gdb (which installs some syscalls xml
files). The locale files could be removed from the binutils
cross-canadian package but we cannot do the same for the syscalls GDB
files which are used by GDB to display user friendly names for the
syscall numbers. Hence, the best solution is to force opkg to overwrite
these files.

[YOCTO #3109]

(From OE-Core rev: 3396545467df05421c3adeb4b5ec532fa95dcb06)

Signed-off-by: Laurentiu Palcu <laurentiu.palcu@intel.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>