ARM: omap1: avoid unused variable warning

The osk_mistral_init() contains code that is only compiled when
CONFIG_PM is set, but it uses a variable that is declared outside
of the #ifdef:

arch/arm/mach-omap1/board-osk.c: In function 'osk_mistral_init':
arch/arm/mach-omap1/board-osk.c:513:7: warning: unused variable 'ret' [-Wunused-variable]

This removes the #ifdef around the user of the variable,
make it always used.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Tony Lindgren <tony@atomide.com>
Acked-by: Aaro Koskinen <aaro.koskinen@iki.fi>