konami/k037122.cpp: Fix max palette numbers of gfxs (#13315)

Author: cam900

src/mame/konami/k037122.cpp

@@ -115,7 +115,7 @@ void k037122_device::device_start()
 	m_tilemap_128->set_transparent_pen(0);
 	m_tilemap_256->set_transparent_pen(0);
 
-	set_gfx(0 ,std::make_unique<gfx_element>(this, k037122_char_layout, (uint8_t *)m_char_ram.get(), 0, entries() / 16, 0));
+	set_gfx(0, std::make_unique<gfx_element>(this, k037122_char_layout, (uint8_t *)m_char_ram.get(), 0, entries() / 256, 0));
 
 	save_pointer(NAME(m_reg), 0x400 / 4);
 	save_pointer(NAME(m_char_ram), 0x200000 / 4);