[PATCH] ARM: Acornfb: Don't claim IRQ fbcon for cursor

The generic fbcon code tries to register and use the vsync IRQ for
ARM platforms with acornfb, but forgets to disable its own cursor
timer.  The result is a flickering flashing cursor.

Remove the code from the fbcon core to register this platform
private interrupt.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>