arm/dt: msm8974: Correct the NoC Priority settings

Currently, device-tree configures the priorities using read and write
priority settings for NoCs. This is incorrect as the driver requires
priority 0 and priority 1 configuration (as opposed to read/write).
This patch ensures priorities are correctly assigned.

Change-Id: I92e28dc6b645cc1748ae3bcca70cd2a9adc6c37e
Signed-off-by: Gagan Mac <gmac@codeaurora.org>