What is the Display IC chip?

I thinks that it is part of the System on Chip Samsung S5L8900 as outlined here and further explained on here

device 0 (17 rec)

"device_type" => 0x757063

"function-cpu_idle" => (8) "\x128N@\x00Iupc"

"reg" => 0x0

"bus-frequency" => 0x0

"peripheral-frequency" => 0x0

"state" => (8) "running\x00"

"timebase-frequency" => 0x0

"memory-frequency" => 0x0

"fixed-frequency" => 0x0

"compatible" => (21) "ARM,1176jzf-s\x00ARM,v6\x00"

"interrupt-parent" => 0x403BD0

"name" => (5) "cpu0\x00"

"clock-frequency" => 0x0

"function-ipi_dispatch" => (12) "\x208;@\x00DIPI\x04\x00\x00\x00"

"interrupts" => (8) "\x04\x00\x00\x00?\x00\x00\x00"

"cpu-version" => 0x0

"AAPL,phandle" => 0x402310

as well as a PowerVR MBX 3D graphics processor:

device 0 (10 rec)

"device_type" => 0x78626D

"clock-ids" => 0x2

"reg" => (8) "\x00\x00\x00\x03\x00\x00\x00\x01"

"power-gates" => 0x2

"clock-gates" => 0x13

"compatible" => (13) "mbx,s5l8900x\x00"

"interrupt-parent" => 0x403BD0

"name" => 0x78626D

"interrupts" => 0xC

"AAPL,phandle" => 0x40C570

check further here and on here

This info from here

Paired with this CPU is a PowerVR MBX-Lite GPU core. This GPU, like the CPU, is built on a 90nm process and is quite simple. The GPU does support hardware transform and lighting but it’s fully fixed function, think of it as a DirectX 6/7 class GPU (Riva TNT2/GeForce 256).

Hope this provides you with the information you needed.