treewide: Fix typos in various parts of the kernel, and fix some comments.

The below patch fixes some typos in various parts of the kernel, as well as fixes some comments.
Please let me know if I missed anything, and I will try to get it changed and resent.

Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/net/irda/nsc-ircc.c

@@ -1664,7 +1664,7 @@ static int nsc_ircc_dma_xmit_complete(struct nsc_ircc_cb *self)
 	switch_bank(iobase, BANK0);
         outb(inb(iobase+MCR) & ~MCR_DMA_EN, iobase+MCR);
 	
-	/* Check for underrrun! */
+	/* Check for underrun! */
 	if (inb(iobase+ASCR) & ASCR_TXUR) {
 		self->netdev->stats.tx_errors++;
 		self->netdev->stats.tx_fifo_errors++;