stlink-1.4.0, fix FL-4356: multilib-strict check failed

[unreg]

Fix:

• https://bugs.funtoo.org/browse/FL-4356
• https://bugs.gentoo.org/630932

Files matching a file type that is not allowed:
   usr/lib/libstlink-shared.so.1.4.0
 * ERROR: dev-embedded/stlink-1.4.0::dev-kit failed:
 *   multilib-strict check failed!

Base:

• On 64-bit system libs installed to /usr/lib instead of /usr/lib64. stlink-org/stlink#633
• https://github.com/texane/stlink/blob/master/doc/compiling.md#build-using-different-directory-for-shared-libs