ext: stm32cube: revert 71ba2de7 and 9a893202

Revert 71ba2de7:
ext: stm32cube: stm32f4xx: shift I2SR field in PLLI2SCFGR register
(ST Bug tracker ID: 50086)

Revert 9a893202:
ext: stm32cube: stm32f7xx: shift I2SR field in PLLI2SCFGR register
(ST Bug tracker ID: 50108)

This two commits were introduced to shift the PLLR parameter according
to the PLL register field position. After analysis, it appears that
function is actually correct, and issue was actually in parameters
provided that didn't match the API. (see PR #12609)

Signed-off-by: Armando Visconti <armando.visconti@st.com>