test: regmap: Increase size of syscon0 memory

test: regmap: Increase size of syscon0 memory

The upcoming changes to the regmap interface will contain a proper check
for plausibility when reading/writing from/to a register map. To still
have the current tests pass, increase the size of the memory region for
the syscon0 device, since one of the tests reads and writes beyond this
range.

Reviewed-by: Anatolij Gustschin <agust@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Mario Six <mario.six@gdsys.cc>