tpm: tis_infineon: Cannot test unsigned for being negative

tpm: tis_infineon: Cannot test unsigned for being negative

tpm_tis_i2c_get_burstcount returns a size_t but also returns -EBUSY if
the TPM is surrently busy. As size_t is an unsigned type simply testing
for < 0 will not work so change the test for being equal to -EBUSY which
will work. Also remove the trivial comments.

This issue was found by Smatch.

Signed-off-by: Andrew Goodbody <andrew.goodbody@linaro.org>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>