drivers:hv: Make a function to free mmio regions through vmbus

This patch introduces a function that reverses everything
done by vmbus_allocate_mmio().  Existing code just called
release_mem_region().  Future patches in this series
require a more complex sequence of actions, so this function
is introduced to wrap those actions.

Signed-off-by: Jake Oshins <jakeo@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/hyperv.h

diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 590fee6..b10954a 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1120,7 +1120,7 @@
 			resource_size_t min, resource_size_t max,
 			resource_size_t size, resource_size_t align,
 			bool fb_overlap_ok);
-
+void vmbus_free_mmio(resource_size_t start, resource_size_t size);
 int vmbus_cpu_number_to_vp_number(int cpu_number);
 u64 hv_do_hypercall(u64 control, void *input, void *output);