board_spisd_initialize() logged "ERROR: Failed to mount the SDCARD" at
every boot when the mount failed. The two usual causes are no card in
the slot and a card with no filesystem. Neither is an error: the block
device is registered, and the card can be formatted with mkfatfs and
mounted later.
Log -EINVAL and -ENODEV from nx_mount() with finfo(). Other errors
are still logged with ferr(), as the rest of the file does.
Also include errno.h, which the file used without including it.
Assisted-by: Claude Code:claude-opus-5-5
Signed-off-by: Marco Casaroli <marco.casaroli@gmail.com>