plnx-deploy.bbclass: Used plm-firmware instead of plm
plnx-deploy.bbclass: Used plm-firmware instead of plm

This patch will use plm-firmware instead of plm.

Signed-off-by: Ashwini Lomate <dd41066105d72f0ca551aeba682181f76e91a868@xilinx.com>

Xilinx/meta-petalinux,Xilinx/meta-petalinux,Xilinx/meta-petalinux,Xilinx/meta-petalinux,Xilinx/meta-petalinux,Xilinx/meta-petalinux