powerpc: Fix iseries drivers build failure without CONFIG_VIOPATH

iSeries dependent drivers fail to build, when CONFIG_VIOPATH is disabled.

Fix the problem by making those drivers select it.

Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 35914b6..f5be808 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -616,6 +616,7 @@
 	default y
 	select HVC_DRIVER
 	select HVC_IRQ
+	select VIOPATH
 	help
 	  iSeries machines support a hypervisor virtual console.