Merge tag 'mailbox-v5.1' of git://git.linaro.org/landing-teams/working/fujitsu/integr...

Pull mailbox updates from Jassi Brar:

 - mailbox-test: support multiple controller instances

 - misc cleanup: IMX, STM32 and Tegra

 - new driver: ZynqMP IPI

* tag 'mailbox-v5.1' of git://git.linaro.org/landing-teams/working/fujitsu/integration:
  mailbox: imx: keep MU irq working during suspend/resume
  dt-bindings: mailbox: Add Xilinx IPI Mailbox
  mailbox: ZynqMP IPI mailbox controller
  mailbox: stm32-ipcc: remove useless device_init_wakeup call
  mailbox: stm32-ipcc: do not enable wakeup source by default
  mailbox: mailbox-test: fix null pointer if no mmio
  mailbox: mailbox-test: fix debugfs in multi-instances
  mailbox: tegra-hsp: mark suspend function as __maybe_unused