mmc: Export host capabilities to debugfs.

This patch exports the host capabilities to debugfs

Signed-off-by: Abbas Raza <Abbas_Raza@mentor.com>
Signed-off-by: Andrew Gabbasov <andrew_gabbasov@mentor.com>
[Harish: Added caps2, moved creation to mmc_add_host_debugfs]
Signed-off-by: Harish Jenny K N <harish_kandiga@mentor.com>
Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>