mmc: block: inline the command abort and start new goto:s

The goto statements sprinkled over the mmc_blk_issue_rw_rq()
function has grown over the years and makes the code pretty hard
to read.

Inline the calls such that:

goto cmd_abort; ->
mmc_blk_rw_cmd_abort(card, req);
mmc_blk_rw_start_new(mq, card, rqc);
return;

goto start_new_req; ->
mmc_blk_rw_start_new(mq, card, rqc);
return;

After this it is more clear how we exit the do {} while
loop in this function, and it gets possible to split the
code apart.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>