ARM: omap1: delete useless interrupt handler

The OMAP1 clocksource interrupt handler just increments a variable
which otherwise isn't used, so this seems to be unnecessary.  Tony
Lindgren confirms, so lets remove it.

Acked-by: Kevin Hilman <khilman@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Cc: linux-omap@vger.kernel.org
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>