vmbus: refactor hv_signal_on_read

vmbus: refactor hv_signal_on_read

BugLink: http://bugs.launchpad.net/bugs/1731926
commit 8dd45f2ab005a1f3301296059b23b03ec3dbf79b upstream.

The function hv_signal_on_read was defined in hyperv.h and
only used in one place in ring_buffer code. Clearer to just
move it inline there.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>