Prompt [Q] Kernel Panic s3cfb on SMDK4412

I am porting OmniROM to UrBetter s702 devices (Hyundai T7s/T7) using the Mixtile Garage board (mixtile.com) as a reference design. The CPU is Exynos4412.
The Mixtile Garage board comes with Linux kernel 3.0.15 and I am trying to update to 3.0.64 using the smdk4412 kernel source tree from Omni.

After creating the necessary mach-mixtile4x12.c file on arch/arm/mach-exynos (using mach-smdk4x12.c as a reference and adapting it, it compiles but on boot is panicking on s3cfb_clk_on: http://paste.omnirom.org/view/0d0fd2ec

The modified kernel tree is here: https://github.com/Frontier314/kernel_smdk4x12
The kernel source is compiled with GCC arm-eabi-4.7; gcc-arm-eabi-4.4.3 has the same problem so it should be something in the source tree.
Any ideas on how to fix this?

Many thanks in advance.