ARM: OMAP4: Fix twd_local_timer_register regression

Commit 7d7e1eba (ARM: OMAP2+: Prepare for irqs.h removal)
changed the interrupts to allow enabling sparse IRQ, but
accidentally added the omap3 INTC base to the local IRQ.
This causes the following:

twd: can't register interrupt 45 (-22)
twd_local_timer_register failed -22

The right fix is to not add any base, as it is a local
timer. For the OMAP44XX_IRQ_LOCALWDT we had defined earlier
there are no users, so no need to fix that.

Reported-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>