gnu: psm2: Update to 11.2.185.

Fixes a bug introduced with the Open MPI 4.1.0 update in commit
ee218032, whereby the new version of
Open MPI would not compile PSM2 support because our version of PSM2 was
too old.  Consequently, Open MPI would fall back to UCX and users would
get poor performance on Omni-Path networks.

* gnu/packages/linux.scm (psm2): Update to 11.2.185.