Fix typos in Documentation/: 'S'

This patch fixes typos in various Documentation txts. The patch addresses
some words starting with the letter 'S'.

Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com>
Acked-by: Alan Cox <alan@redhat.com>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

Documentation/dvb/cards.txt

@@ -5,7 +5,7 @@ Hardware supported by the linuxtv.org DVB drivers
   frontends (i.e. tuner / demodulator units) used, usually without
   changing the product name, revision number or specs. Some cards
   are also available in versions with different frontends for
-  DVB-S/DVB-C/DVB-T. Thus the frontend drivers are listed seperately.
+  DVB-S/DVB-C/DVB-T. Thus the frontend drivers are listed separately.
 
   Note 1: There is no guarantee that every frontend driver works
   out of the box with every card, because of different wiring.