Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/Documentation/dvb/README.dvb-usb b/Documentation/dvb/README.dvb-usb
index c8238e4..c4d963a 100644
--- a/Documentation/dvb/README.dvb-usb
+++ b/Documentation/dvb/README.dvb-usb
@@ -138,7 +138,7 @@
 in the device).
 
 If you want to enable debug output, you have to load the driver manually and
-from withing the dvb-kernel cvs repository.
+from within the dvb-kernel cvs repository.
 
 first have a look, which debug level are available: