mailbox: mailbox-test: handle channel errors consistently

mbox_test_request_channel() returns either an ERR_PTR or NULL. The
callers, however, mostly checked for non-NULL which allows for bogus
code paths when an ERR_PTR is treated like a valid channel. A later
commit tried to fix it in one place but missed the other ones. Because
the ERR_PTR is only used for -ENOMEM once and is converted to
-EPROBE_DEFER anyhow, convert the callee to only return NULL which
simplifies handling a lot and makes it less error prone.

Fixes: 8ea4484d0c2b ("mailbox: Add generic mechanism for testing Mailbox Controllers")
Fixes: 9b63a810c6f9 ("mailbox: mailbox-test: Fix an error check in mbox_test_probe()")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>

0 files changed, 0 insertions, 0 deletions