spi: Prepare cleanup of powerpc's asm/prom.h

powerpc's asm/prom.h brings some headers that it doesn't
need itself.

In order to clean it up, first add missing headers in
users of asm/prom.h
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/5ed3298d8b5b1b5bf681d79584c61cb495852f4e.1648833423.git.christophe.leroy@csgroup.euSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-mpc52xx-psc.c

@@ -20,6 +20,7 @@
 #include <linux/spi/spi.h>
 #include <linux/fsl_devices.h>
 #include <linux/slab.h>
+#include <linux/of_irq.h>
 
 #include <asm/mpc52xx.h>
 #include <asm/mpc52xx_psc.h>

drivers/spi/spi-mpc52xx.c

@@ -19,6 +19,9 @@
 #include <linux/io.h>
 #include <linux/of_gpio.h>
 #include <linux/slab.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
 #include <asm/time.h>
 #include <asm/mpc52xx.h>