media: anysee: accept read buffers of length 1 in anysee_master_xfer

anysee_master_xfer currently accepts read messages of length 2 only.
However, several frontends, e.g. tda10023 send buffers of length 1,
containing an 8-bit register number (see tda10023_readreg).
These buffers are rejected currently, making many Anysee variants
to not work. In these cases the "Unsupported Anysee version"
message is logged.

This patch alters the function to accept buffers of a length of 1 too.

Signed-off-by: István Váradi <ivaradi@varadiistvan.hu>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
[hverkuil: add spaces around '<', fix typo in 'sevaral']