drivers/shared_irq: fix kconfig hierarchy

Add a menu to enclose all the shared IRQ kconfig options.

Change-Id: I8083204c53f60022c06e9c683fa9544fdc278f32
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
diff --git a/drivers/shared_irq/Kconfig b/drivers/shared_irq/Kconfig
index d48cc0a..d5bf4bf 100644
--- a/drivers/shared_irq/Kconfig
+++ b/drivers/shared_irq/Kconfig
@@ -16,7 +16,7 @@
 # limitations under the License.
 #
 
-config SHARED_IRQ
+menuconfig SHARED_IRQ
 	bool
 	prompt "Shared interrupt driver"
 	default n
@@ -97,7 +97,7 @@
 
 config SHARED_IRQ_1
 	bool "Shared interrupt instance 1"
-	select SHARED_IRQ
+	depends on SHARED_IRQ
 	help
 	 Provide an instance of the shared interrupt driver when system
 	 configuration requires that multiple devices share an interrupt.