tpm/tpm_i2c_infineon: Add small comment about return value of __i2c_transfer

Kent Yoder indicated that the code might be a bit clearer with a comment
here, so this patch adds a small explanation of the code.

Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>
1 file changed