tpm: xen-tpmfront: Fix default durations

All the default durations were being set to 10 minutes which is
way too long for the timeouts. Normal values for the longest
duration are around 5 mins, and short duration ar around .5s.

Further, these are just the default, tpm_get_timeouts will set
them to values from the TPM (or throw an error).

Just remove them.

Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>