Sansa Connect: fix a likely typo in busy wait loop in USB driver
GCC 9.5 issues a -Wmisleading-indentation warning due to an extra
semicolon at the end of the while loop. It does seem unintentional
since the loop is a busy wait, so remove the semicolon.
Change-Id: I83b8676cbf38434b8148c43906c6bba9c16d036e