mpi3mr: Decrement per controller and per target counter post reset

Post controller reset, If any device removal events arrive, and if
there are any outstanding IOs then the driver will unnecessarily wait
in the loop for 30 seconds before removing the device from the OS.

reset target outstanding IO counter and controller outstanding IO counter
and remove the redundant wait loop.

Reviewed by: imp
Approved by: imp
Differential revision: https://reviews.freebsd.org/D44424

(cherry picked from commit 571f1d0638fa6b3a08f84118a33e53f941f0820c)