clk: ti: OMAP4: Remove the legacy timer DT clock aliases

The DT clock aliases for timers using the legacy OMAP timer
device names have been cleaned up. These device names reflect
the names used in legacy boot, and are no longer applicable
as OMAP4 is DT boot only now.

Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>