Remove the device-ID one-shot: it made Swiss see no adapter at all

id_phase was set at reset and cleared permanently by the GC's first NCRA reset,
after which a command-space read of register 0 returned 0x00000000.  Swiss
calls EXI_GetID from bba_exists() AND again from bba_requires_init(), long
after init, and matches the result against EXI_MX98730EC_ID -- so with the
one-shot spent no case matched and Swiss reported NO ADAPTER, not a broken one.
Running gc_bba_test was enough to spend it, so the adapter would "disappear"
after any test session.

The justification in the comment was wrong.  It claimed the fast path would
otherwise hijack address 0 so the GC could never read NCRA back -- but NCRA is
REGISTER space (0x80/0xC0 header) while the fast path requires byte 0 == 0x00,
i.e. COMMAND space.  They were never ambiguous, and no driver reads command
register 0 for anything else (libogc2 reads 0x01/0x03/0x0B/0x0F, Swiss 0x03).
Real hardware answers EXI_GetID whenever asked; that is how EXI enumerates
devices.

id_arm is now tied high, and the id_phase output, the FFSynchronizer that
crossed it into the pin domain, and the BBATop wiring are all gone.  The port
stays only so the PHASE_METER build can disarm the fast path, which would
otherwise send ID bytes instead of its constant 0x80.

bba_top T1b reads the device ID AFTER an NCRA reset, which T1 (before any
reset) structurally cannot catch.  Mutation-tested: disarming the fast path
returns 00 00 00 00 for both, exactly what Swiss saw.

gc_bba_test: the ID tests no longer skip.  A wrong ID is a FAILURE again, with
no iface_alive() discrimination and no ordering requirement between suites --
the ID is readable at any point in a run.  g_ncra_reset_done and iface_alive()
are removed outright rather than left as a dead flag.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

gc_bba_test/source/tests.h

@@ -31,7 +31,6 @@ extern const int g_nsuites;
  * clears id_phase in the gateware, after which address 0 reads back NCRA.
  * That is correct behaviour (it matches the GC's own init order), but it
  * means the ID test can only pass once per console power cycle. */
-extern int g_ncra_reset_done;
 
 void tests_run_test(test_t *t);
 void tests_run_suite(suite_t *s);