[pwm, doc] Fix paths of pwm documents
[pwm, doc] Fix paths of pwm documents

Signed-off-by: Tung Hoang <301b2712f51eb2109af58545896b2fa10cf1f4c6@wdc.com>

lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan