[Bug target/78275] New: [avr] at43usb320 in wrong multilib set.

["gjl at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78275

            Bug ID: 78275
           Summary: [avr] at43usb320 in wrong multilib set.
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gjl at gcc dot gnu.org
  Target Milestone: ---

avr-mcus.def currenly lists at43usb320 as belonging to avr31.  This is not
correct because the device can only handle 64 KiB of (external) program memory
but avr31 is for devices with 128 KiB (supports ELPM which is not supported by
at43usb320).

As the data sheet does not mention the exact instruction set supported, it's
unclear if avr3 is the correct multilib (likely) or avr35 (if MOVW) or even
avr5 (of MUL).