Better IRX error handling

[israpps]

IRX ID must be > 0, else, an error ocurred while loading the module (see kerr.h on IOP Kernel)

return value can be 0, 1 or 2 (ref)

It could mean an error or not depending on the module behaviour, but for all the modules you use, returning 1 means an error. 0: module remains on RAM 1: module requested to be unloaded during startup (eg: error, or module does not require to remain resident) 2: module remains on RAM, but supports to be unloaded anytime by MODLOAD, (only if both module and MODLOAD version support it)