ARM: OMAP1: ams-delta: Fix broken GPIO ID allocation

In order to request dynamic allocationn of GPIO IDs, a negative number
should be passed as a base GPIO ID via platform data.  Unfortuntely,
commit 771e53c4 ("ARM: OMAP1: ams-delta: Drop board specific global
GPIO numbers") didn't follow that rule while switching to dynamically
allocated GPIO IDs for Amstrad Delta latches, making their IDs
overlapping with those already assigned to OMAP GPIO devices.  Fix it.

Fixes: 771e53c4 ("ARM: OMAP1: ams-delta: Drop board specific global GPIO numbers")
Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
Cc: stable@vger.kernel.org
Acked-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Tony Lindgren <tony@atomide.com>