[PATCH] drivers: mmc: support secure erase.

[dennis laplacian1]

Hi Jaehoon Chung,
for your comment:
"ditto. if (IS_ENABLED()) instead of #if.
And i don't know why doesn't check this in mmc_erase_t().
Then it doesn't need to pass arg as argument."

I check the support of secure erase in the mmc_berase and not in
mmc_erase_t because mmc_erase_t is called multiple times for each block.
So to prevent unnecessary checks, I check the support in mmc_berase
function.