mit-krb5.pc: Add missing -lkrb5profile

Fixes the ports that prefer static linking:
https://reviews.freebsd.org/D49277

Approved by: re (cperciva)
Reviewed by: ivy, dch, cy
Sponsored by: SkunkWerks, GmbH
Differential Revision: https://reviews.freebsd.org/D52910

(cherry picked from commit 2d9fd2c573c318754e3f36d2549e0e57ce199d60)
(cherry picked from commit 771ee17c88106fb07b5035a2f36c36ccafe94edd)