mmc: st: correct retries management

The retries number should be 3.
A warning message is added in mmc_block_read(), and the code is refactored.

Change-Id: I577c7dd91c451c7580b1660042cb5fe26ee3fa12
Signed-off-by: Yann Gautier <yann.gautier@st.com>
2 files changed