ARM: dts: BCM63xx: Fix incorrect interrupt specifiers

A number of our interrupts were incorrectly specified, fix both the PPI
and SPI interrupts to be correct.

Fixes: b5762cac ("ARM: bcm63138: add NAND DT support")
Fixes: 46d4bca0 ("ARM: BCM63XX: add BCM63138 minimal Device Tree")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>