Pull mailbox updates from Jassi Brar:
- New Hi3660 mailbox driver
- Fix TEGRA Kconfig warning
- Broadcom: use dma_pool_zalloc instead of dma_pool_alloc+memset
* tag 'mailbox-v4.17' of git://git.linaro.org/landing-teams/working/fujitsu/integration:
mailbox: Add support for Hi3660 mailbox
dt-bindings: mailbox: Introduce Hi3660 controller binding
mailbox: tegra: relax TEGRA_HSP_MBOX Kconfig dependencies
maillbox: bcm-flexrm-mailbox: Use dma_pool_zalloc()