ata: sata_sx4: Add error handling in pdc20621_i2c_read()

The function pdc20621_prog_dimm0() calls the function pdc20621_i2c_read()
but does not handle the error if the read fails. This could lead to
process with invalid data. A proper implementation can be found in
/source/drivers/ata/sata_sx4.c, pdc20621_prog_dimm_global(). As mentioned
in its commit: bb44e154, the variable spd0
might be used uninitialized when pdc20621_i2c_read() fails.

Add error handling to pdc20621_i2c_read(). If a read operation fails,
an error message is logged via dev_err(), and return a negative error
code.

Add error handling to pdc20621_prog_dimm0() in pdc20621_dimm_init(), and
return a negative error code if pdc20621_prog_dimm0() fails.

Fixes: 4447d351 ("libata: convert the remaining SATA drivers to new init model")
Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>