DPS310 sampling

[Matt Spinler]

Hi Joel,

Now that phosphor-hwmon-readd tries to read the DPS310 temp, we keep 
hitting EAGAINs from the driver.  It turns out that the delay call 
within phosphor-hwmon doesn't always wait a full second because it pops 
out of the delay if there is some dbus work to handle.  It would take a 
nontrivial refactoring to fix that properly, and I think even if we did 
we'd just barely be avoiding a race between that being done and the temp 
being available every 1s.

What do you think of changing the rate to be faster than 1 measurement 
per second?  Is that a device tree binding?  In combination with that 
change and phosphor-hwmon doing retries, we should be able to get things 
to work.

Alternatively I could just add in up to a second of retries from within 
phosphor-hwmon, but that would slow down users that request data from it 
on dbus.