Pull mailbox updates from Jassi Brar.
* 'mailbox-for-next' of git://git.linaro.org/landing-teams/working/fujitsu/integration:
mailbox/bcm2835: Fix mailbox full detection.
dt: mailbox: Remove 'mbox-names property is discouraged' message from binding
mailbox: Add ability for clients to request channels by name
mailbox: Enable BCM2835 mailbox support
dt/bindings: Add binding for the BCM2835 mailbox driver
mailbox: Fix up error handling in mbox_request_channel()
mailbox: Make mbox_chan_ops const
mailbox: altera: Add dependency on HAS_IOMEM