powerpc/83xx: add a const qualifier
powerpc/83xx: add a const qualifier

This prepares *of_device_id.data becoming const. Without this change
the following warning would occur:

	arch/powerpc/platforms/83xx/suspend.c: In function 'pmc_probe':
	arch/powerpc/platforms/83xx/suspend.c:336:7: error: assignment discards 'const' qualifier from pointer target type [-Werror]

Acked-by: Benjamin Herrenschmidt <a7089bb6e7e92505d88aaff006cbdd60cc9120b6@kernel.crashing.org>
Signed-off-by: Uwe Kleine-König <181323dd666a182bc2d953e52d0ac3ab54cd8391@pengutronix.de>

KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs