Revert "soc: intel_adsp: fix linker script for cavs_v20"

This reverts commit 3cc14b2c.

Revert this due to the same reason as commit
a29b66bb:

  Unfortunately this mechanism doesn't seem to actually work on the SDK
  linker.  The emitted sections, when passed a symbol name as the "start
  address" just appear wherever the "." variable was pointing (in this
  case, into the cached region).  That breaks the kernel coherence
  layer, obviously.

Signed-off-by: Daniel Leung <daniel.leung@intel.com>