test/py: mmc: Fix 'mmc info' testcase

Commit 41e30dcf ("cmd: mmc: Make Mode: printout consistent") fixed
the layout of `mmc info` output.  Reflect this change in the respective
testcase.

Also fix a typo in the documentation.

Fixes: 41e30dcf ("cmd: mmc: Make Mode: printout consistent")
Signed-off-by: Harald Seiler <hws@denx.de>
Acked-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Simon Glass <sjg@chromium.org>