lirc_imon: add some defines for display types and don't use larger buffer
lirc_imon: add some defines for display types and don't use larger buffer

- add enum for dislpay types for readability
- only do usb_match_id for display type lists if display_type is auto-detect
- revert to 4-byte buffer on LCD devices, it *should* work.

stb-tester/lirc,stb-tester/lirc,stb-tester/lirc,stb-tester/lirc,stb-tester/lirc,stb-tester/lirc