[SYCL][E2E] Remove FPGA support from E2E tests

[ayylol]

First of multiple PRs to remove FPGA support from DPC++ (See #16929).

This PR removes support for FPGAs from the sycl E2E tests. Note that instead of lit quitting with an error if an unsupported device is available, I am switching the behaviour to issue a warning so that it does not crash currently if an FPGA device is available.