ARM: pxa: fix pxa3xx DFI lockup hack

Some recently added code to avoid a bug introduced a build error
when CONFIG_PM is disabled and a macro is hidden:

arch/arm/mach-pxa/pxa3xx.c: In function 'pxa3xx_init':
arch/arm/mach-pxa/pxa3xx.c:439:3: error: 'NDCR' undeclared (first use in this function)
   NDCR = (NDCR & ~NDCR_ND_ARB_EN) | NDCR_ND_ARB_CNTL;
   ^

This moves the macro outside of the #ifdef so it can be
referenced correctly.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: adf3442c

 ("ARM: pxa: fix DFI bus lockups on startup")
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>