remoteproc: Fall back to using parent memory pool if no dedicated available

commit db9178a4

 upstream.

In some cases, like with OMAP remoteproc, we are not creating dedicated
memory pool for the virtio device. Instead, we use the same memory pool
for all shared memories. The current virtio memory pool handling forces
a split between these two, as a separate device is created for it,
causing memory to be allocated from bad location if the dedicated pool
is not available. Fix this by falling back to using the parent device
memory pool if dedicated is not available.

Cc: stable@vger.kernel.org
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Acked-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Fixes: 086d0872

 ("remoteproc: create vdev subdevice with specific dma memory pool")
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Suman Anna <s-anna@ti.com>
Link: https://lore.kernel.org/r/20200420160600.10467-2-s-anna@ti.com
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>