doc: kernel: move polling/interrupts out of other/

Move out of others and make those two sections part of the core kernel
documentation.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
diff --git a/doc/kernel/index.rst b/doc/kernel/index.rst
index c62f0b3..7bd0b67 100644
--- a/doc/kernel/index.rst
+++ b/doc/kernel/index.rst
@@ -35,8 +35,8 @@
    threads/system_threads.rst
    threads/workqueue.rst
    threads/nothread.rst
-   other/interrupts.rst
-   other/polling.rst
+   interrupts.rst
+   polling.rst
    synchronization/semaphores.rst
    synchronization/mutexes.rst
    synchronization/condvar.rst
diff --git a/doc/kernel/other/interrupts.rst b/doc/kernel/interrupts.rst
similarity index 100%
rename from doc/kernel/other/interrupts.rst
rename to doc/kernel/interrupts.rst
diff --git a/doc/kernel/other/polling.rst b/doc/kernel/polling.rst
similarity index 100%
rename from doc/kernel/other/polling.rst
rename to doc/kernel/polling.rst