omap: remove dead wdt code in plat-omap/devices.c

Commit f2ce6231 (OMAP: WDT: Split OMAP1 and OMAP2PLUS device
registration) removed omap_init_wdt and related structures from
plat-omap/devices.c. However a subsequent commit or merge
seems to have reintroduced these by accident. The caller of
omap_init_wdt was also removed by that commit, and this did
not get restored. So we have the following build warning now:

  CC      arch/arm/plat-omap/devices.o
arch/arm/plat-omap/devices.c:252: warning: 'omap_init_wdt' defined but not used

Fix this by removing this dead code.

Signed-off-by: Anand Gadiyar <gadiyar@ti.com>
Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>