-Updated description of some fields of these registers: REG_CHAN_CNTRL_1,
REG_CHAN_CNTRL_2, REG_CHAN_CNTRL_3, REG_CHAN_CNTRL_4, REG_USR_CNTRL_4,
and REG_USR_CNTRL_5
-Added two new registers, both with their own fields and description:
REG_CHAN_CNTRL_9 and REG_CHAN_CNTRL_10
Signed-off-by: Cristian Mihai Popa <cristianmihai.popa@analog.com>