[media] m5mols: Simplify the I2C registers definition

The redundant definitions of the m5mols I2C register addresses within
the pages (categories) are removed. In place of symbolic definitions
plain numbers are used which simplifies the code and eases identifying
the registers in the documentation.

Also make the m5mols_busy() function accept I2C_REG() value as a register
address, like all other functions, rather than using the category and
command values.

Acked-by: HeungJun Kim <riverful.kim@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>