libstb: bump up the byte timeout for tpm i2c requests
libstb: bump up the byte timeout for tpm i2c requests

This bumps up the byte timeout for tpm i2c requests from 10ms to 30ms.
Some p8dtu systems are getting i2c request timeout.

Signed-off-by: Claudio Carvalho <e431f4b4a17082357e3d270b337bd485cc81832b@linux.vnet.ibm.com>
Signed-off-by: Stewart Smith <ec31ab75ddf977353c8f660f92ea8b23f64aef25@linux.vnet.ibm.com>

qemu/skiboot,mikey/skiboot,shenki/skiboot,stewart-ibm/skiboot,open-power/skiboot,stewart-ibm/skiboot,legoater/skiboot,shenki/skiboot,legoater/skiboot,legoater/skiboot,open-power/skiboot,mikey/skiboot,legoater/skiboot,stewart-ibm/skiboot,shenki/skiboot,mikey/skiboot,legoater/skiboot,open-power/skiboot,qemu/skiboot,shenki/skiboot,open-power/skiboot,open-power/skiboot,qemu/skiboot,shenki/skiboot,qemu/skiboot,qemu/skiboot