otLogPlat() function

Emits a log message at given log level using a platform module name. This is is intended for use by platform. If `OPENTHREAD_CONFIG_LOG_PLATFORM` is not set or the current log level is below @p aLogLevel , this function does not emit any log message. The @p aPlatModuleName name is used to determine the log module name in the emitted log message, following the `P-{PlatModuleName}---` format. This means that the prefix string "P-" is added to indicate that this is a platform sub-module, followed by the next 12 characters of the @p PlatModuleName string, with padded hyphens `-` at the end to ensure that the region name is 14 characters long.