[media] m5mols: add m5mols_read_u8/u16/u32() according to I2C byte width

[media] m5mols: add m5mols_read_u8/u16/u32() according to I2C byte width

For now, the m5mols_read() share in case of I2C packet 1, 2, 4 byte(s) width.
So, this commit adds 3 functions - m5mols_read_u8/u16/u32() according to byte
width of I2C packet. And, the u32 variables in spite of u8 or u16 for fitting
to m5mols_read() having no choice, is replaced to have original byte width
like u8, u16, u32 as same reason.

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