iio: magnetometer: rm3100: add boundary check for the value read from RM3100_REG_TMRC

In the Linux kernel, the following vulnerability has been resolved: iio: magnetometer: rm3100: add boundary check for the value read from RM3100_REG_TMRC Recently, we encounter kernel crash in function rm3100_common_probe caused by out of bound access of array rm3100_samp_rates (because of underlying hardware failures). Add boundary check to prevent out of bound access.