trivial: Fix misspelling of firmware

Fix misspelling of firmware.

Signed-off-by: Nick Andrew <nick@nick-andrew.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Documentation/powerpc/dts-bindings/fsl/cpm_qe/qe/firmware.txt

@@ -1,6 +1,6 @@
 * Uploaded QE firmware
 
-      If a new firwmare has been uploaded to the QE (usually by the
+      If a new firmware has been uploaded to the QE (usually by the
       boot loader), then a 'firmware' child node should be added to the QE
       node.  This node provides information on the uploaded firmware that
       device drivers may need.