clock_control: fix to get PLL2 source for PREDV1 working

Some fixes where needed to get PLL2 source of PREVI1 functional.
Compiled ok with following configuration:
CONFIG_CLOCK_STM32F10X_CONN_LINE_PREDIV1_SRC_PLL2CLK=y
CONFIG_CLOCK_STM32F10X_CONN_LINE_PREDIV2=0
CONFIG_CLOCK_STM32F10X_CONN_LINE_PLL2_MULTIPLIER=8

Jira: ZEP-1758

Change-Id: I5ddfaef1b44c4c4e5e6adedc158a1c9092bc8df5
Signed-off-by: Erwan Gouriou <erwan.gouriou@linaro.org>
1 file changed