[DRA7][TIMESTAMP] Fix 32k counter register address

Actually, OMAP5 and DRA7 share the same register address, not OMAP4.

Fix the same.

Fixes commit a7361b40320d2121daf0d481ec9892418546b9c6 ([DRA7][TIMESTAMP]
Provide 32k counter register address)

Signed-off-by: Edward Shin <e-shin@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>