sfc: document devlink flash support

Update the information in sfc's devlink documentation including
support for firmware update with devlink flash.
Also update the help text for CONFIG_SFC_MTD, as it is no longer
strictly required for firmware updates.

Signed-off-by: Edward Cree <[e-mail]>
Link: https://patch.msgid.link/3476[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

Documentation/networking/devlink/sfc.rst

···
 ===================
 
 This document describes the devlink features implemented by the ``sfc``
-device driver for the ef100 device.
+device driver for the ef10 and ef100 devices.
 
 Info versions
 =============
···
    * - Name
      - Type
      - Description
+   * - ``fw.bundle_id``
+     - stored
+     - Version of the firmware "bundle" image that was last used to update
+       multiple components.
    * - ``fw.mgmt.suc``
      - running
      - For boards where the management function is split between multiple
···
    * - ``fw.uefi``
      - running
      - UEFI driver version (No UNDI support).
+
+Flash Update
+============
+
+The ``sfc`` driver implements support for flash update using the
+``devlink-flash`` interface. It supports updating the device flash using a
+combined flash image ("bundle") that contains multiple components (on ef10,
+typically ``fw.mgmt``, ``fw.app``, ``fw.exprom`` and ``fw.uefi``).
+
+The driver does not support any overwrite mask flags.

drivers/net/ethernet/sfc/Kconfig

···
 	default y
 	help
 	  This exposes the on-board flash and/or EEPROM as MTD devices
-	  (e.g. /dev/mtd1).  This is required to update the firmware or
-	  the boot configuration under Linux.
+	  (e.g. /dev/mtd1).  This is required to update the boot
+	  configuration under Linux, or use some older userland tools to
+	  update the firmware.
 config SFC_MCDI_MON
 	bool "Solarflare SFC9100-family hwmon support"
 	depends on SFC && HWMON && !(SFC=y && HWMON=m)