The below patch should get you going with L2 Cache enabled on GIT kernel, tested on Beagle board.
Regards,
Khasim
--- ../my_linux_omap/arch/arm/mm/Kconfig 2008-05-06 16:37:17.000000000 +0530
+++ arch/arm/mm/Kconfig 2008-05-07 12:40:05.000000000 +0530
@@ -659,6 +659,20 @@ config CPU_DCACHE_SIZE
If your SoC is configured to have a different size, define the value
here with proper conditions.
+choice
+ prompt "L2 Cache Size"
+ depends on ARCH_OMAP34XX