Fix some common typos

ChangeLog

@@ -5333,7 +5333,7 @@
 	* arch/arm/src/sama5/sam_memories.c and .h:  Centralize logic for
 	  conversions between physical and virtual addresses (2013-8-9).
 	* arch/arm/src/sama5/sam_hsmci.c and sam34/sam_hsmci.c:  Correct a
-	  race condition in the SAMA5 HSCMI driver:  The tranfer done
+	  race condition in the SAMA5 HSCMI driver:  The transfer done
 	  interrupt was firing before the wait was started.  Fix this and
 	  also backported the changes to SAM3/4 (untested).  Now HSCMI is
 	  functional on the SAMA5 with DMA! (2013-8-10).
@@ -10383,7 +10383,7 @@
 	  corrected implementation of pthread_kill() will direct the signal
 	  specifically to the specific pthread and no other (2015-05-13).
 	* arch/arm/include/samdl, arch/arm/src/samdl, configs/samd20-xplained:
-	  Rename the samd/ directories and configuratino varialbes to samdl to
+	  Rename the samd/ directories and configuration varialbes to samdl to
 	  all the same directory structure to support the SAML21 (2015-05-14).
 	* arch/arm/include/samdl and arch/arm/src/samdl: And chip definitions,
 	  configuration framework, and placeholder memory map and pin

drivers/net/e1000.c

@@ -1128,8 +1128,8 @@ static int e1000_probe(uint16_t addr, pci_id_t id)
    * access performance. The page size alloc will restrict
    * this bad effect only within the memory we alloc here.
    *
-   * NEED FIX: the memalign may alloc memory continous in
-   * virtual address but dis-continous in physical address
+   * NEED FIX: the memalign may alloc memory continuous in
+   * virtual address but dis-continuous in physical address
    * due to RGMP memory setup.
    */
 

drivers/usbdev/usbmsc_scsi.c

@@ -2281,7 +2281,7 @@ static int usbmsc_cmdwritestate(FAR struct usbmsc_dev_s *priv)
       xfrd            = req->xfrd;
       priv->nreqbytes = xfrd;
 
-      /* Now loop until all of the data in the read request has been tranferred
+      /* Now loop until all of the data in the read request has been transferred
        * to the block driver OR all of the request data has been transferred.
        */