pn54x: Remove unused variables

Follow-up to commit 064f9628367aa8ae383133f9eaa081248ab2c241.

Bug: 66996870
Test: mmma system/nfc/halimpl/pn54x
Exempt-From-Owner-Approval: Build fix
Change-Id: I8e97a7312cb2d84de9945fa242718fdfa367a885
1 file changed