mmc: core: Export device lifetime information through sysfs

mmc: core: Export device lifetime information through sysfs

In the eMMC 5.0 version of the spec, several EXT_CSD fields about
device lifetime are added.

 - Two types of estimated indications reflected by averaged wear out of memory
 - An indication reflected by average reserved blocks

Export the information through sysfs.

Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>
Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>