ASoC: Intel: Skylake: Remove second shim read in register_poll

No need to read the register again if the value read has already matched
the target during the loop. So remove the second shim read.

Signed-off-by: Subhransu S. Prusty <subhransu.s.prusty@intel.com>
Signed-off-by: Guneshwor Singh <guneshwor.o.singh@intel.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>