i2c: imx: fix missing stop condition in single-master mode

i2c: imx: fix missing stop condition in single-master mode

A regression was introduced with the implementation of single-master
mode, preventing proper stop conditions from being generated. Devices
that require a valid stop condition, such as EEPROMs, fail to function
correctly as a result.

The issue only affects devices with the single-master property enabled.

This commit resolves the issue by re-enabling I2C bus busy bit (IBB)
polling for single-master mode when generating a stop condition. The fix
further ensures that the i2c_imx->stopped flag is cleared at the start
of each transfer, allowing the stop condition to be correctly generated
in i2c_imx_stop().

According to the reference manual (IMX8MMRM, Rev. 2, 09/2019, page
5270), polling the IBB bit to determine if the bus is free is only
necessary in multi-master mode. Consequently, the IBB bit is not polled
for the start condition in single-master mode.

Fixes: 6692694aca86 ("i2c: imx: do not poll for bus busy in single master mode")
Signed-off-by: Stefan Eichenberger <stefan.eichenberger@toradex.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Link: https://lore.kernel.org/r/20241216151829.74056-1-eichest@gmail.com
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>