Some controllers require waiting for the bus to become idle
before writing to some registers. I have implemented this
by adding a hook to sd_ctrl_write16() and implementing
a hook for SDHI which waits for the bus to become idle.

Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Magnus Damm <magnus.damm@gmail.com>
Signed-off-by: NSimon Horman <horms@verge.net.au>
Signed-off-by: NChris Ball <cjb@laptop.org>

This reflects at least the current usage of this register
and I think it improves the readability of the code ever so slightly.

Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Magnus Damm <magnus.damm@gmail.com>
Signed-off-by: NSimon Horman <horms@verge.net.au>
Signed-off-by: NChris Ball <cjb@laptop.org>

Standardize the checks for multiple MMC header file inclusion,
including adding comments to terminating #endif's, and fixing
one incorrect comment.
Signed-off-by: NRobert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: NChris Ball <cjb@laptop.org>

Also add TMIO_BBS.

This allows these defines to also be used by zboot.

Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: NSimon Horman <horms@verge.net.au>
Signed-off-by: NGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: NPaul Mundt <lethal@linux-sh.org>
Signed-off-by: NChris Ball <cjb@laptop.org>