trivial: fix then -> than typos in comments and documentation

- (better, more, bigger ...) then -> (...) than

Signed-off-by: Frederik Schwarzer <schwarzerf@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/mtd/devices/pmc551.c b/drivers/mtd/devices/pmc551.c
index d38bca6..d2fd550 100644
--- a/drivers/mtd/devices/pmc551.c
+++ b/drivers/mtd/devices/pmc551.c
@@ -34,7 +34,7 @@
  *	aperture size, not the dram size, and the V370PDC supplies no
  *	other method for memory size discovery.  This problem is
  *	mostly only relevant when compiled as a module, as the
- *	unloading of the module with an aperture size smaller then
+ *	unloading of the module with an aperture size smaller than
  *	the ram will cause the driver to detect the onboard memory
  *	size to be equal to the aperture size when the module is
  *	reloaded.  Soooo, to help, the module supports an msize