package/devmem2: remove package

package/devmem2: remove package

It was here just for backwards compatibility and is not used by any
package or board after commits

  59856480b6 packages/devmem2: remove from all board configurations
  2f6e3eae55 package/ti-gfx: do not use devmem2 in script

There are address casting issues with 32bit access on a 64bit bus (like
on the SoC FPGA ARM processors) with this tool. The Busybox version of
devmem is the most up to date and supports quadword access.

Fixes: https://bugs.busybox.net/show_bug.cgi?id=10171
Signed-off-by: Carlos Santos <unixmania@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>