mailbox: apcs-ipc: Add compatible string for atoll

Add compatible string in mailbox driver to match trinket
apcs_glb and apcs_glb2 device nodes

Change-Id: I67b27e8497d720f874db048b5d0ca39a1f0b0b68
Signed-off-by: Deepak Kumar Singh <deesin@codeaurora.org>