Fix write8() to route SPU register writes through writeRegister

On real hardware, byte stores to SPU MMIO addresses write the full
16-bit value. Mirrors the existing check in write16().

Signed-off-by: Nicolas 'Pixel' Noble <nicolas@nobis-crew.org>

Author: nicolasnoble

src/core/psxhw.cc

@@ -480,6 +480,11 @@ void PCSX::HW::write8(uint32_t add, uint32_t rawvalue) {
             g_emulator->m_mem->initMsan(value);
             break;
         default:
+            if ((hwadd >= 0x1f801c00) && (hwadd < 0x1f801e00)) {
+                g_emulator->m_spu->writeRegister(add, (uint16_t)rawvalue);
+                break;
+            }
+
             if (addressInRegisterSpace(hwadd)) {
                 uint32_t *ptr = (uint32_t *)&g_emulator->m_mem->m_hard[hwadd & 0xffff];
                 *ptr = SWAP_LEu32(rawvalue);