tty: hvc: 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/8b3dbd25bbeb7949e1b0a2170fee7b9cc5a6f806.1648833418.git.christophe.leroy@csgroup.euSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/hvc/hvc_opal.c

@@ -13,12 +13,12 @@
 #include <linux/slab.h>
 #include <linux/console.h>
 #include <linux/of.h>
+#include <linux/of_irq.h>
 #include <linux/of_platform.h>
 #include <linux/export.h>
 #include <linux/interrupt.h>
 
 #include <asm/hvconsole.h>
-#include <asm/prom.h>
 #include <asm/firmware.h>
 #include <asm/hvsi.h>
 #include <asm/udbg.h>

drivers/tty/hvc/hvc_vio.c

@@ -28,10 +28,10 @@
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/console.h>
+#include <linux/of.h>
 
 #include <asm/hvconsole.h>
 #include <asm/vio.h>
-#include <asm/prom.h>
 #include <asm/hvsi.h>
 #include <asm/udbg.h>
 #include <asm/machdep.h>

drivers/tty/hvc/hvsi.c

@@ -26,13 +26,13 @@
 #include <linux/module.h>
 #include <linux/major.h>
 #include <linux/kernel.h>
+#include <linux/of_irq.h>
 #include <linux/spinlock.h>
 #include <linux/sysrq.h>
 #include <linux/tty.h>
 #include <linux/tty_flip.h>
 #include <asm/hvcall.h>
 #include <asm/hvconsole.h>
-#include <asm/prom.h>
 #include <linux/uaccess.h>
 #include <asm/vio.h>
 #include <asm/param.h>