docs: driver-api: firmware_loader: fix missing argument in usage example

By the time firmware-upload support landed in commit 97730bbb242c
("firmware_loader: Add firmware-upload support"), the arguments for
firmware_upload_register() had changed, and while this is automagically
represented in the kernel doc bits, the usage example was not kept in
sync.
Add the missing argument as per the driver.

Fixes: 97730bbb242c ("firmware_loader: Add firmware-upload support")
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230329123425.4177084-1-conor.dooley@microchip.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

firmware_loader: Add sysfs nodes to monitor fw_upload

Add additional sysfs nodes to monitor the transfer of firmware upload data
to the target device:

cancel: Write 1 to cancel the data transfer
error: Display error status for a failed firmware upload
remaining_size: Display the remaining amount of data to be transferred
status: Display the progress of the firmware upload

Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Tianfei zhang <tianfei.zhang@intel.com>
Tested-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
Signed-off-by: Russ Weight <russell.h.weight@intel.com>
Link: https://lore.kernel.org/r/20220421212204.36052-6-russell.h.weight@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

firmware_loader: Add firmware-upload support

Extend the firmware subsystem to support a persistent sysfs interface that
userspace may use to initiate a firmware update. For example, FPGA based
PCIe cards load firmware and FPGA images from local FLASH when the card
boots. The images in FLASH may be updated with new images provided by the
user at his/her convenience.

A device driver may call firmware_upload_register() to expose persistent
"loading" and "data" sysfs files. These files are used in the same way as
the fallback sysfs "loading" and "data" files. When 0 is written to
"loading" to complete the write of firmware data, the data is transferred
to the lower-level driver using pre-registered call-back functions. The
data transfer is done in the context of a kernel worker thread.

Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Tianfei zhang <tianfei.zhang@intel.com>
Tested-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
Signed-off-by: Russ Weight <russell.h.weight@intel.com>
Link: https://lore.kernel.org/r/20220421212204.36052-5-russell.h.weight@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>