cross-canadian.bbclass: fix rpath for sdk executables

cross-canadian.bbclass: fix rpath for sdk executables

This makes the libraries located in places like this findable:
/usr/local/oecore-x86_64/sysroots/x86_64-oesdk-linux/usr/lib

Which avoids linking cross canadian sdk executables with host libraries like this:

$ ldd /usr/local/oecore-x86_64/sysroots/x86_64-oesdk-linux/usr/bin/x86_64-oe-linux/x86_64-oe-linux-gdb
        linux-vdso.so.1 =>  (0x00007fffb7fff000)
        libreadline.so.6 => /usr/local/oecore-x86_64/sysroots/x86_64-oesdk-linux/usr/lib/x86_64-oe-linux/../libreadline.so.6 (0x00007fbfb5511000)
        libdl.so.2 => /usr/local/oecore-x86_64/sysroots/x86_64-oesdk-linux/lib/libdl.so.2 (0x00007fbfb530c000)
        libncurses.so.5 => /usr/local/oecore-x86_64/sysroots/x86_64-oesdk-linux/lib/libncurses.so.5 (0x00007fbfb50e9000)
        libtinfo.so.5 => /usr/local/oecore-x86_64/sysroots/x86_64-oesdk-linux/lib/libtinfo.so.5 (0x00007fbfb4ec2000)
        libz.so.1 => /usr/local/oecore-x86_64/sysroots/x86_64-oesdk-linux/usr/lib/x86_64-oe-linux/../libz.so.1 (0x00007fbfb4cac000)
        libm.so.6 => /usr/local/oecore-x86_64/sysroots/x86_64-oesdk-linux/lib/libm.so.6 (0x00007fbfb4a2a000)
        libpthread.so.0 => /usr/local/oecore-x86_64/sysroots/x86_64-oesdk-linux/lib/libpthread.so.0 (0x00007fbfb480d000)
        libutil.so.1 => /usr/local/oecore-x86_64/sysroots/x86_64-oesdk-linux/lib/libutil.so.1 (0x00007fbfb4609000)
        libexpat.so.1 => /usr/local/oecore-x86_64/sysroots/x86_64-oesdk-linux/usr/lib/x86_64-oe-linux/../libexpat.so.1 (0x00007fbfb43e0000)
        libc.so.6 => /usr/local/oecore-x86_64/sysroots/x86_64-oesdk-linux/lib/libc.so.6 (0x00007fbfb4059000)
        /usr/local/oecore-x86_64/sysroots/x86_64-oesdk-linux/lib/ld-linux-x86-64.so.2 => /lib64/ld-linux-x86-64.so.2 (0x0000003f05000000)

[RP: Whitespace tweaks]
Signed-off-by: Nitin A Kamble <nitin.a.kamble@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>