V4L/DVB (9043): S5H1420: Fix size of shadow-array to avoid overflow

The array size of 'shadow' still needs to be fixed in order to not overflow when reading register 0x00.

Thanks to Oliver Endriss for pointing that out.

Signed-off-by: Patrick Boettcher <pb@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>