gpu_counter_producer: Remove unnecessary c flags

Bug: http://b/259559364
Bug: http://b/267819531

Both these flags are added by the build system.  Adding -pie to a
compile command causes an unused argument warning.  This is exposed by
aosp/2585150 which turns the warning back on.

Test: build with aosp/2585150
Change-Id: If723215882c332a7e2cb51ab425d7031a26d87c3