Remove duplicated register load in function call to quick entry.

CallRuntimeHelperRegLocation() will load parameter to registers for native call, but
GenConversionCall() duplicates the work before it call CallRuntimeHelperRegLocation().

Instructions generated before patch:
      0xf731007e: f8d9e25c	ldr.w   lr, [r9, #604]  ; pF2l
      0xf7310082: ee180a10	vmov.f32 r0, s16
      0xf7310086: ee180a10	vmov.f32 r0, s16
      0xf731008a: 47f0    	blx     lr
After:
      0xf739707e: f8d9e25c	ldr.w   lr, [r9, #604]  ; pF2l
      0xf7397082: ee180a10	vmov.f32 r0, s16
      0xf7397086: 47f0    	blx     lr

Change-Id: I1868aefa4703a0f8133eaac707f5b80f01293cb8