[PATCH 0/1] MR696: mfreadwrite/reader: Only attempt to copy sample buffers from responses with non-NULL samples.

[Henri Verbeet (＠hverbeet)]

For example, queueing a MF_SOURCE_READERF_ENDOFSTREAM response will set
a NULL sample. This fixes a regression introduced by commit
68fa3f673633c138596b86ad2ed1befcd0cc63c5.