ARM: ux500: disable msp2 node on Snowball

ARM: ux500: disable msp2 node on Snowball

Analogous to commit ecdbd1f24cc3a7377756b1de138384ce801a9241
that fixed commit 6ace9ca83f26c
"ARM: ux500: move MSP pin control to the device tree"
accidentally activated MSP2, giving rise to a boot scroll
scream as the kernel attempts to probe a driver for it and
fails to obtain DMA channel 14.

For some reason I forgot to fix this on the Snowball. Fix
this up by marking the node disabled again.

Cc: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Kevin Hilman <khilman@linaro.org>