Documentation: fix sysfs-ptp

s/avaiable/available/g

This fixup is already in scripts/spelling.txt.

The fix in Documentation/ABI/testing/sysfs-ptp affects documentation of
a /sys entry: the /sys entry itself is correct.
Signed-off-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Documentation/ABI/testing/sysfs-ptp

@@ -74,7 +74,7 @@ Description:
 		assignment may be changed by two writing numbers into
 		the file.
 
-What:		/sys/class/ptp/ptpN/pps_avaiable
+What:		/sys/class/ptp/ptpN/pps_available
 Date:		September 2010
 Contact:	Richard Cochran <richardcochran@gmail.com>
 Description:

Documentation/sysctl/vm.txt

@@ -135,7 +135,7 @@ Contains, as a percentage of total available memory that contains free pages
 and reclaimable pages, the number of pages at which the background kernel
 flusher threads will start writing out dirty data.
 
-The total avaiable memory is not equal to total system memory.
+The total available memory is not equal to total system memory.
 
 ==============================================================
 
@@ -170,7 +170,7 @@ Contains, as a percentage of total available memory that contains free pages
 and reclaimable pages, the number of pages at which a process which is
 generating disk writes will itself start writing out dirty data.
 
-The total avaiable memory is not equal to total system memory.
+The total available memory is not equal to total system memory.
 
 ==============================================================