ARM: dt: Use the 'model' field for printing the hardware revision

When booting a device tree kernel, we get the following output from
'cat /proc/cpuinfo':

$ cat /proc/cpuinfo
processor       : 0
model name      : ARMv7 Processor rev 5 (v7l)
BogoMIPS        : 531.66
Features        : swp half thumb fastmult vfp edsp neon vfpv3 tls
CPU implementer : 0x41
CPU architecture: 7
CPU variant     : 0x2
CPU part        : 0xc08
CPU revision    : 5

Hardware        : Freescale i.MX51 (Device Tree Support)
Revision        : 0000
Serial          : 0000000000000000

The Hardware line does not really describe the hardware type, as it is reading
the information from the dt 'machine' field.

In the dt case, read the 'model' field instead, so that we can have a better
description output as follows:

Hardware        : Freescale i.MX51 Babbage Board

The hardware output string is unchanged for the non-dt kernel case.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
ARM: mxs: Print silicon version on boot

Introduce functions that identify the SoC type (i.MX23 or iMX28)
and also report the silicon revision.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
ARM: mxs: Pass the system revision

Some mxs userspace tools, such as multimedia plugins and kobs-ng (tool used to
burn boot images to NAND) rely on the 'Revision' field reported by
'/proc/cpuinfo'.

Provide a mechanism to pass such information, so that now we can get:

$ cat /proc/cpuinfo
processor       : 0
model name      : ARM926EJ-S rev 5 (v5l)
BogoMIPS        : 226.09
Features        : swp half fastmult edsp java
CPU implementer : 0x41
CPU architecture: 5TEJ
CPU variant     : 0x0
CPU part        : 0x926
CPU revision    : 5

Hardware        : Freescale i.MX28 Evaluation Kit
Revision        : 28012
Serial          : 0000000000000000

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>