Merge branch 'mailbox-for-next' of git://git.linaro.org/landing-teams/working/fujitsu/integration

Pull mailbox updates from Jassi Brar:

 - mailbox bindings and drivers for
     * APM X-Gene
     * Hisilicon Hi6220
     * Rockchip RK3368
   platforms

 - minor fixes to the above three drivers.

 - misc cleanups of mailbox-test driver.

* 'mailbox-for-next' of git://git.linaro.org/landing-teams/working/fujitsu/integration:
  mailbox: rockchip: avoid 64-bit division
  mailbox: rockchip: Add Rockchip mailbox driver
  dt-bindings: rockchip-mailbox: Add mailbox controller document on Rockchip SoCs
  mailbox/xgene-slimpro: Checking for IS_ERR instead of NULL
  mailbox: Hi6220: add mailbox driver
  dt-bindings: mailbox: Document Hi6220 mailbox driver
  mailbox: mailbox-test: add support for separate tx/rx buffer with single channel
  mailbox: mailbox-test: use print_hex_dump_bytes to allow dynamic printk
  mailbox: mailbox-test: fix the compatible string
  mailbox: mailbox-test: rename driver as generic test driver
  Documentation: mailbox: Add APM X-Gene SLIMpro mailbox dts documentation
  mailbox: Add support for APM X-Gene platform mailbox driver