Fix typos in /Documentation : 'U-Z'

This patch fixes typos in various Documentation txts. The patch addresses some
+words starting with the letters 'U-Z'.

Looks like I made it through the alphabet...just in time to start over again
+too!  Maybe I can fit more profound fixes into the next round...?  Time will
+tell. :)

Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index 2ffb0d6..0543162 100644
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -489,7 +489,7 @@
 flags can be or'd together and are
 
 DMA_MEMORY_MAP - request that the memory returned from
-dma_alloc_coherent() be directly writeable.
+dma_alloc_coherent() be directly writable.
 
 DMA_MEMORY_IO - request that the memory returned from
 dma_alloc_coherent() be addressable using read/write/memcpy_toio etc.