Fix 'install_rom' rule for 'HAL'
Detail: Since srcbuild treats HAL type components as "not C" during the install ROM phase, yet the HAL fragment inherits most of its rules from CModule, there's no install_rom rule to override (as there is with AAsmModule, for example) so no need to suffix it with ${CUSTOM_ROM}. This was preventing the link and copy step for clients of the HAL fragment. !NoTag