Used sparse_copy API in favor of dd/cp in rawcopy plugin to
preserve sparseness of the copied raw content.
[YOCTO #9099]
(From OE-Core rev: 04eca59068a79ae6a9969be495c4cdf0c5c3e466)
Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>