firmware: arm_scmi: Fix the build when CONFIG_MAILBOX is not selected

0day CI kernel test robot reported following build error with randconfig

aarch64-linux-ld: drivers/firmware/arm_scmi/driver.o:(.rodata+0x1e0):
		undefined reference to `scmi_mailbox_desc'

Fix the error by adding CONFIG_MAILBOX dependency for scmi_mailbox_desc.

Link: https://lore.kernel.org/r/[email protected]
Cc: Etienne Carriere <[email protected]>
Cc: Cristian Marussi <[email protected]>
Reviewed-by: Etienne Carriere <[email protected]>
Reviewed-by: Cristian Marussi <[email protected]>
Tested-by: Cristian Marussi <[email protected]>
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Sudeep Holla <[email protected]>

0 files changed, 0 insertions, 0 deletions