docs: correct the firmware split — graphics needs a Windows blob too

I had this wrong. The claim that accelerated graphics works on the firmware
Fedora ships does not survive contact with the device tree.

Fedora does package an sdm845/a630_zap.mbn, which is what led me astray, but
that is the generic Snapdragon 845 zap shader. The C630's node in
sdm850-lenovo-yoga-c630.dts names qcom/sdm850/LENOVO/81JL/qcdxkmsuc850.mbn
specifically — model-signed, present only in the machine's Windows partition.
Until it is supplied the display is unaccelerated.

Also add qcslpi850.mbn and qcvss850.mbn, which were missing entirely, and
attribute the sensor hub to slpi_pas rather than cdsp_pas. The list is now
every firmware-name property in the mainline device tree rather than a
recollection of forum posts, so it should be complete: eight files, not five.

WiFi and Bluetooth are unaffected — ath10k WCN3990 including wlanmdsp.mbn is
genuinely redistributable and genuinely shipped.

Add a section on locating the blobs on an old backup, for the case where
Windows is long gone from the machine.

Only comments changed in config/packages/base.pkgs, so the package set hashes
identically and the staged base stays valid.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XWRjNJMistCy6ngXH5aJLS

overlay/etc/motd.d/c630.in

@@ -1,7 +1,7 @@
 
   Fedora @FEDORA_RELEASE@ for the @DEVICE_DESC@  (built @BUILD_DATE@ from @BUILD_REF@)
 
-  Graphics and WiFi work with the firmware Fedora ships. Audio, the sensor
-  hub and hardware video decode need per-model blobs from the Windows
-  partition — run `sudo c630-firmware` once to extract them.
+  WiFi and Bluetooth work with the firmware Fedora ships. Accelerated
+  graphics, audio, the sensor hub and video decode all need per-model blobs
+  from the Windows partition — run `sudo c630-firmware` once to extract them.