libhidl: allocate rarely used regex only if needed

Essentially, only lshal (commandline tool) uses this.

Bug: 150319735
Test: boot
Change-Id: I61ef4de29dd6f30361e7ef67b8d6f150ed519735
(cherry picked from commit ccc3a974c0dd1c274e16798e052f879b202ac6a5)
Merged-In: I61ef4de29dd6f30361e7ef67b8d6f150ed519735
1 file changed