DPC++ daily 2022-08-04

[SYCL][FPGA] Remove support for intel::fpga_pipeline attribute (#6519)

Support for new FPGA attribute called [[intel::fpga_pipeline(N)]]
on https://github.com/intel/llvm/pull/6254 is no longer needed.

This patch removes the support from frontend.

Signed-off-by: Soumi Manna <soumi.manna@intel.com>