input: TSC: ti_tscadc: Correct register usage

This patch cleans up the wrong register definitions
and usage for touchscreen controller.
Bit masks were not defined earlier.

For ex: consider a register define as:
write(xyz, ABC)
ABC is expected to be written to register bits 0-11.
Here we see that value written is as expected, but this write
is also affecting all the remaining bits of xyz.
The remaining bits hold the default value as 0 and the write
also sets it to zero. Hence wrong usage were not causing user
visible bugs.
Due to these reasons it was difficult to follow when
compared with TRM.

Unused definitions are also removed.
Since there is change in some naming convention because of
all the above mentioned reasons, the same has been
updated throughout the code.
Bit declarations are grouped to increase readability.

Signed-off-by: Patil, Rachna <rachna@ti.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>