Merge remote-tracking branch 'remotes/xtensa/tags/20181125-xtensa' into staging

xtensa fixes for 3.1:

- fix register counting logic for linux-user gdbserver;
- provide default memory sizes for XTFPGA boards;
- add missing xtensa patterns to MAINTAINTERS.

# gpg: Signature made Sun 25 Nov 2018 23:07:54 GMT
# gpg:                using RSA key 51F9CC91F83FA044
# gpg: Good signature from "Max Filippov <filippov@cadence.com>"
# gpg:                 aka "Max Filippov <max.filippov@cogentembedded.com>"
# gpg:                 aka "Max Filippov <jcmvbkbc@gmail.com>"
# Primary key fingerprint: 2B67 854B 98E5 327D CDEB  17D8 51F9 CC91 F83F A044

* remotes/xtensa/tags/20181125-xtensa:
  MAINTAINERS: add missing xtensa patterns
  target/xtensa: xtfpga: provide default memory sizes
  target/xtensa: drop num_[core_]regs from dc232b/dc233c configs
  target/xtensa: gdbstub fix register counting

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>