Clock recovery violated: what to do?

The clocks are not synchronous, i.e. your recovery requirement is probably some really small number that's impossible to meet. And you really can't transfer a signal between a 100MHz clock and 175MHz clock in a synchronous manner.

Note that all clocks are related by default in TimeQuest, and it is up to the user to put cut the analysis between domains. SOPC Builder will not automatically add this timing constraints because it doesn't know for certain that you want them cut. If you make them separate clocks in SOPC builder, it will build logic to handle them as if they were asynchronous, it just won't create the .sdc constraints.

Since there are impossible to be synchronous, you absolutely want to false path them. If you have a set_clock_groups constraint in your design(I generally recommend it), then make sure they're in separate groups. Otherwise you could do:

set_false_path -from [get_clocks 100MHz] -to [get_clocks 175MHz]

set_false_path -from [get_clocks 175MHz] -to [get_clocks 100MHz]

(Where you replace the name 100MHz and 175MHz with the correct PLL clock name.)