clocksource/drivers/imx-tpm: Add different counter width support

Different TPM modules have different width counters which is 16-bit or 32-bit,
the counter width can be read from TPM_PARAM register bit[23:16], this patch
adds dynamic check for counter width to support both 16-bit and 32-bit TPM
modules.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>