Time initialization performed in init_teecore()

Time initialization was performed in specific platform initialization
main_init_helper() function. It is now performed in the generic arm32
initialization init_teecore() function.

Signed-off-by: Pascal Brand <pascal.brand@st.com>
Reviewed-by: Joakim Bech joakim.bech@linaro.org
Reviewed-by: Jens Wiklander jens.wiklander@linaro.org