[media] tc358743: don't use variable length array for I2C writes

drivers/media/i2c/tc358743.c:148:19: warning: Variable length array is used.

As the maximum size is 1026, we can't use dynamic var, as it
would otherwise spend 1056 bytes of the stack at i2c_wr() function.

So, allocate a buffer with the allowed maximum size together with
the state var.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Acked-by: Mats Randgaard <matrandg@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>