Pull mailbox updates from Jassi Brar:
- Introduce device-managed registration
devm_mbox_controller_un/register and convert drivers to use it
- Introduce flush api to support clients that must busy-wait in atomic
context
- Support multiple controllers per device
- Hi3660: a bugfix and constify ops structure
- TI-MsgMgr: off by one bugfix.
- BCM: switch to spdx license
- Tegra-HSP: support for shared mailboxes and suspend/resume.
* tag 'mailbox-v4.21' of git://git.linaro.org/landing-teams/working/fujitsu/integration: (30 commits)
mailbox: tegra-hsp: Use device-managed registration API
mailbox: tegra-hsp: use devm_kstrdup_const()
mailbox: tegra-hsp: Add suspend/resume support
mailbox: tegra-hsp: Add support for shared mailboxes
dt-bindings: tegra186-hsp: Add shared mailboxes
mailbox: Allow multiple controllers per device
mailbox: Support blocking transfers in atomic context
mailbox: ti-msgmgr: Use device-managed registration API
mailbox: stm32-ipcc: Use device-managed registration API
mailbox: rockchip: Use device-managed registration API
mailbox: qcom-apcs: Use device-managed registration API
mailbox: platform-mhu: Use device-managed registration API
mailbox: omap: Use device-managed registration API
mailbox: mtk-cmdq: Remove needless devm_kfree() calls
mailbox: mtk-cmdq: Use device-managed registration API
mailbox: xgene-slimpro: Use device-managed registration API
mailbox: sti: Use device-managed registration API
mailbox: altera: Use device-managed registration API
mailbox: imx: Use device-managed registration API
mailbox: hi6220: Use device-managed registration API
...