Add copy of f_accessory.h.

Newer kernels have deleted the f_accerroy.h file and the functionality
is changing. Add a copy of the file for use by this code since the
kernel 6.8 headers will delete it permanently.

Bug: 329038193

Test: Builds.
Change-Id: Iaa379ef507e8d4b902231505902dccb35c3a2a0b