[CORE] devtree: Add generic device tree node matching API

This patch moves the device tree node matching API from vmm_devdrv and vmm_devemu to vmm_devtree.

In fact, all commonly required device tree operations should be part of vmm_devtree.

Signed-off-by: Anup Patel <anup@brainfault.org>
[CORE] devemu: Remove use of typedefs and have pointer to emulator in emulated device

Signed-off-by: Anup Patel <anup@brainfault.org>
Merge remote-tracking branch 'upstream/master'