feat: include vortex fexp RTL

src/main/scala/radiance/tile/VortexCore.scala

@@ -360,6 +360,7 @@ class Vortex(tile: RadianceTile)(implicit p: Parameters)
   addResource("/vsrc/vortex/hw/rtl/fpu/VX_fpu_div.sv")
   addResource("/vsrc/vortex/hw/rtl/fpu/VX_fpu_dpi.sv")
   addResource("/vsrc/vortex/hw/rtl/fpu/VX_fpu_dsp.sv")
+  addResource("/vsrc/vortex/hw/rtl/fpu/VX_fpu_exp.sv")
   addResource("/vsrc/vortex/hw/rtl/fpu/VX_fpu_fma.sv")
   addResource("/vsrc/vortex/hw/rtl/fpu/VX_fpu_ncomp.sv")
   addResource("/vsrc/vortex/hw/rtl/fpu/VX_fpu_rounding.sv")