Documentation/arm/IXP4xx fix a typo

Corrected the word softare to software.
Signed-off-by: Stefan Huber <steffhip@googlemail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Documentation/arm/IXP4xx

@@ -36,7 +36,7 @@ Linux currently supports the following features on the IXP4xx chips:
 - Timers (watchdog, OS)
 
 The following components of the chips are not supported by Linux and
-require the use of Intel's proprietary CSR softare:
+require the use of Intel's proprietary CSR software:
 
 - USB device interface
 - Network interfaces (HSS, Utopia, NPEs, etc)