drivers: i2c_ll_stm32_v1: Fix RX for all receptions

This patch fixes the read operation of the I2C driver
for all the receptions (1-byte, 2-bytes, N-bytes when
N > 2)

Signed-off-by: Yannis Damigos <giannis.damigos@gmail.com>
Tested-by: Yannis Damigos <giannis.damigos@gmail.com>
Tested-by: Martin Iñaki Malerba <inakimmalerba@gmail.com>