target/hexagon: move GETPC() calls to top level helpers

target/hexagon: move GETPC() calls to top level helpers

As docs/devel/loads-stores.rst states:

  ``GETPC()`` should be used with great care: calling
  it in other functions that are *not* the top level
  ``HELPER(foo)`` will cause unexpected behavior. Instead, the
  value of ``GETPC()`` should be read from the helper and passed
  if needed to the functions that the helper calls.

Let's fix the GETPC() usage in Hexagon, making sure it's always called
from top level helpers and passed down to the places where it's
needed. There are a few snippets where that is not currently the case:

- probe_store(), which is only called from two helpers, so it's easy to
  move GETPC() up.

- mem_load*() functions, which are also called directly from helpers,
  but through the MEM_LOAD*() set of macros. Note that this are only
  used when compiling with --disable-hexagon-idef-parser.

  In this case, we also take this opportunity to simplify the code,
  unifying the mem_load*() functions.

- HELPER(probe_hvx_stores), when called from another helper, ends up
  using its own GETPC() expansion instead of the top level caller.

Signed-off-by: Matheus Tavares Bernardino <quic_mathbern@quicinc.com>
Reviewed-by: Taylor Simpson <ltaylorsimpson@gmail.com>
Message-Id: <2c74c3696946edba7cc5b2942cf296a5af532052.1689070412.git.quic_mathbern@quicinc.com>-ne
Reviewed-by: Brian Cain <bcain@quicinc.com>
Signed-off-by: Brian Cain <bcain@quicinc.com>
Message-Id: <20231008220945.983643-2-bcain@quicinc.com>