powerpc/warp: Fix ISA_DMA_THRESHOLD default
powerpc/warp: Fix ISA_DMA_THRESHOLD default

If no device is passed to __dma_alloc_coherent, it defaults to using ISA_DMA_THRESHOLD
for the mask. This patch provides a reasonable default rather than 0.

Signed-off-by: Sean MacLennan <080046d26665d55357d58d1570fdcf552c1e43f1@pikatech.com>
Signed-off-by: Benjamin Herrenschmidt <a7089bb6e7e92505d88aaff006cbdd60cc9120b6@kernel.crashing.org>

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