rx: Don't have 2 different protos for rxi_CheckCall

rx: Don't have 2 different protos for rxi_CheckCall

Use a single prototype for rxi_CheckCall in both the pthread and
lwp cases. Remove the #ifdef maze at the call sites, and take advantage
of the fact that MUTEX_EXIT reduces to an empty string in the lwp
case.

Change-Id: Iaa8c1b983f1c8372e9c2e1b90aaef25a2bc5f81f
Reviewed-on: http://gerrit.openafs.org/8291
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>