timer: fttmr010: return a previously deleted driver now ported to DM

timer: fttmr010: return a previously deleted driver now ported to DM

The fttmr010 timer driver was deleted by
commit 29fc6f24926e ("ARM: remove a320evb board support")
The original source file was: arch/arm/cpu/arm920t/a320/timer.c

Return the driver to the codebase in a DM compatible form.
A platform using fttmr010 will be submitted later.

This hardware is described in the datasheet [1], starting from page 348.
According to the datasheet, there is a Revision Register at offset 0x3C,
which is not present in 'struct fttmr010'. Add it and debug() print
revision in probe function.

[1]
https://bitbucket.org/Kasreyn/mkrom-uc7112lx/src/master/documents/FIC8120_DS_v1.2.pdf

Signed-off-by: Sergei Antonov <saproj@gmail.com>