platform/x86: pmc_atom: remove unused pmc_atom_write()

platform/x86: pmc_atom: remove unused pmc_atom_write()

This function isn't used anywhere in the driver or anywhere in tree.
So remove it.  It can always be re-added if/when a use arises.

Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Aubrey Li <aubrey.li@linux.intel.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Mark Gross <markgross@kernel.org>
Cc: platform-driver-x86@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Link: https://lore.kernel.org/r/20220428062430.31010-2-paul.gortmaker@windriver.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>