Update readme.md

Update Blue and Black Wireless revisions to first production models. U-boot needs to be changed to respect all revisions.

readme.md

@@ -21,12 +21,10 @@ BeagleBoard.org or Element14 BeagleBone Black:
 
 BeagleBoard.org BeagleBone Blue:
 
-      A0: [aa 55 33 ee 41 33 33 35  42 4e 4c 54 42 4c 41 30 |.U3.A335BNLTBLA0|]
-      A1: [aa 55 33 ee 41 33 33 35  42 4e 4c 54 42 4c 41 30 |.U3.A335BNLTBLA1|]      
+      A2: [aa 55 33 ee 41 33 33 35  42 4e 4c 54 42 4c 41 30 |.U3.A335BNLTBLA2|]
 
 BeagleBoard.org BeagleBone Black Wireless:
 
-      A3: [aa 55 33 ee 41 33 33 35  42 4e 4c 54 42 57 41 33 |.U3.A335BNLTBWA3|]
       A5: [aa 55 33 ee 41 33 33 35  42 4e 4c 54 42 57 41 33 |.U3.A335BNLTBWA5|]
 
 SeeedStudio BeagleBone Green: