serial: MMIO32 support for 8250_early.c

Provide MMIO32 support in 8250_early (aka earlycon)

[randy.dunlap@oracle.com: fix printk format warnings]
[akpm@linux-foundation.org: fix printk args some more]
Signed-off-by: Samium Gromoff <_deepfire@feelingofgreen.ru>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Documentation/kernel-parameters.txt

@@ -681,8 +681,11 @@ and is between 256 and 4096 characters. It is defined in the file
 	earlycon=	[KNL] Output early console device and options.
 		uart[8250],io,<addr>[,options]
 		uart[8250],mmio,<addr>[,options]
+		uart[8250],mmio32,<addr>[,options]
 			Start an early, polled-mode console on the 8250/16550
 			UART at the specified I/O port or MMIO address.
+			MMIO inter-register address stride is either 8bit (mmio)
+                        or 32bit (mmio32).
 			The options are the same as for ttyS, above.
 
 	earlyprintk=	[X86,SH,BLACKFIN]