[PATCH v2] firmware: raspberrypi: Change dependency to ARCH_BCM2835 and COMPILE_TEST

[Chen-Yu Tsai <wenst@chromium.org>]

The Raspberry Pi firmware driver has no compile dependencies on the
BCM2835 mailbox driver. It's just a indirect runtime dependency: the
driver only works on a Raspberry Pi.

Change the dependency from BCM2835_MBOX to ARCH_BCM2835. Also allow
compile tests. This allows drivers that have build time dependencies
on this firmware driver to be compile tested as well. More dependencies
are added to account for build time dependencies:

  - depends on MAILBOX for mailbox API (not stubbed) usage
  - depends on ARM || ARM64 for dsb() usage

Also make it built by default if ARCH_BCM2835, since many functions will
not work without this firmware driver.

Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
---
Changes since v1:
- Added depends on MAILBOX for API usage (pointed out by Sashiko)
- Added depends on ARM || ARM64 for dsb() usage
  (build failure report from kernel test robot)
- Added default ARCH_BCM2835 as Florian suggested
---
 drivers/firmware/Kconfig | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index bbd2155d8483..bcfda01c2ab8 100644
--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig
@@ -114,7 +114,10 @@ config ISCSI_IBFT
 
 config RASPBERRYPI_FIRMWARE
 	tristate "Raspberry Pi Firmware Driver"
-	depends on BCM2835_MBOX
+	depends on ARCH_BCM2835 || COMPILE_TEST
+	depends on ARM || ARM64
+	depends on MAILBOX
+	default ARCH_BCM2835
 	help
 	  This option enables support for communicating with the firmware on the
 	  Raspberry Pi.
-- 
2.54.0.rc2.544.gc7ae2d5bb8-goog