mmc: arm_pl180_mmci: update arm_pl180_mmci_init() prototype

Update arm_pl180_mmci_init() prototype by adding struct mmc**
param. This is needed before converting this driver to driver model
in order to use arm_pl180_mmci_init() in driver model and in none
driver model implementation

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>