fix(plat/st): correct IO compensation disabling
fix(plat/st): correct IO compensation disabling

In stm32mp1_syscfg_disable_io_compensation(), to disable the IO
compensation cell, we have to set the corresponding bit in
SYSCFG_CMPENCLRR register, instead of clearing the bit in SETR register.

Change-Id: I510a50451f8afb9e98c24e1ea84efbf73a39e6b4
Signed-off-by: Yann Gautier <e753f6969c288905606e3c07464886d4f1fc1be0@st.com>

achingupta/arm-trusted-firmware,achingupta/arm-trusted-firmware