Graphics: For TPC platforms, put splashscreen in-kernel

TPCs currently do not have a splashscreen. Additionally, the TS-7990 does, but it is only in the bootloader which can cause RGB LCD interface to not get clocks after the kernel starts booting until it is ready to start driving the display normally. Adding console framebuffer decreases this transition time, but negatively affects the TS-7553-V2 mono LCD.