misc: fastrpc: fix improper packet size calculation

commit 3a1bf591 upstream.

The buffer list is sorted and this is not being considered while
calculating packet size. This would lead to improper copy length
calculation for non-dmaheap buffers which would eventually cause
sending improper buffers to DSP.

Fixes: c68cfb71 ("misc: fastrpc: Add support for context Invoke method")
Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Jeya R <jeyr@codeaurora.org>
Link: https://lore.kernel.org/r/1637771481-4299-1-git-send-email-jeyr@codeaurora.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>