vndk-def: Add (vndk-sp)? to fwk-only-rs matching

This commit adds (?:vndk-sp)? to FWK-ONLY-RS matching because some
targets have a copy of libft2.so in /system/lib[64]/vndk-sp but we still
want to treat it as FWK-ONLY-RS.

Bug: 37867089
Test: libft2.so is not labeled as vndk-sp-indirect in sailfish image.
Merged-In: Iad5db6417573f3e25bad5c027cb547d9df4be23a
(cherry picked from commit 6582daf9)

Change-Id: I2a6c9741444739d56d0db00792f2bc4ffd417125