remoteproc: Add inline coredump functionality

remoteproc: Add inline coredump functionality

The current coredump implementation uses vmalloc area to copy
all the segments. But this might put strain on low memory targets
as the firmware size sometimes is in tens of MBs. The situation
becomes worse if there are multiple remote processors undergoing
recovery at the same time. This patch adds inline coredump
functionality that avoids extra memory usage. This requires
recovery to be halted until data is read by userspace and free
function is called.

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Sibi Sankar <sibis@codeaurora.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Rishabh Bhatnagar <rishabhb@codeaurora.org>
Tested-by: Sibi Sankar <sibis@codeaurora.org>
Link: https://lore.kernel.org/r/1594938035-7327-5-git-send-email-rishabhb@codeaurora.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>