A problem about EMMC support

[SlarkXiao]

When flash a partition with 'sparse="true"' flag, no error returned.
But device can't boot up successfully and it reports corresponding partition mount failed.
According to the Windows tool, it has split image up into 4 partitions and then write 1 by 1.
It seems we don't obtain such mechanism.

Test log as below from windows QFIL:
xml:

QFIL log:
INFO: File system.img is a sparse file, being split up into 4 separate XML tags
......
INFO: system.img is a sparse image
INFO: Looking for file 'system.img'
INFO: system.img is a sparse image
INFO: Looking for file 'system.img'
INFO: system.img is a sparse image
INFO: Looking for file 'system.img'
INFO: system.img is a sparse image
INFO: Looking for file 'system.img'
......
system.img is a sparse image
{ (68.80 MB) 140912 sectors needed at location 3031040 on LUN 0}
{ (8.00 KB) 16 sectors needed at location 3293184 on LUN 0}
{ (8.00 KB) 16 sectors needed at location 3293320 on LUN 0}
{ (119.97 MB) 245696 sectors needed at location 3297336 on LUN 0

[SlarkXiao]

Actually this is issue was caused by the sparse image format. We shall transfer it to RAW image format.