drivers: i2c: stm32: remove redundant new line

LOG_* adds "\n" by itself.

Fixes redundant lines during startup:

```
[00:00:00.100,000] <inf> i2c_ll_stm32_v2: I2C TIMING = 0xb0f6343d

[00:00:00.100,000] <inf> i2c_ll_stm32_v2: I2C TIMING = 0xb0f6343d

[00:00:00.100,000] <inf> i2c_ll_stm32_v2: I2C TIMING = 0xb0f6343d

[00:00:00.100,000] <inf> i2c_ll_stm32_v2: I2C TIMING = 0xb0f6343d

[00:00:00.100,000] <inf> flash_stm32_qspi: Reading SFDP
```

Signed-off-by: Nerijus Bendžiūnas <nerijus.bendziunas@astrolightspace.com>