mmc: dw_mmc: Avoid adding the number of transmitted bytes twice

mmc: dw_mmc: Avoid adding the number of transmitted bytes twice

Previously, it was possible to add either 0 bytes or add nbytes
twice if we broke out of the outer loop and then carry on to the
"done" label. This is now fixed by adding the transferred bytes
right after the pull/pop operation

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Acked-by: Jaehoon Chung <jh80.chung@samsung.com>
Acked-by: Seungwon Jeon <tgih.jun@samsung.com>
Signed-off-by: Chris Ball <cjb@laptop.org>