use std::pow in order to avoid compile time errors like: error: call of overloaded 'pow(int, uint16_t&)' is ambiguous
use std::pow in order to avoid compile time errors like:
error: call of overloaded 'pow(int, uint16_t&)' is ambiguous

as seen on SunOS 5.11

Change-Id: I0e0bcdf4c50f9c8d1e8f088193eac82247178e80
Reviewed-on: https://gerrit.libreoffice.org/14478
Tested-by: David Tardon <120ec0d1a1a64b2795847ed1f99512646e9f2768@redhat.com>
Reviewed-by: David Tardon <120ec0d1a1a64b2795847ed1f99512646e9f2768@redhat.com>

LibreOffice/libmspub,LibreOffice/libmspub,LibreOffice/libmspub