bcm_sta: update to 6.20.155.1

move 5.100.82.112 patches to their own folder for safekeeping then add
patches for 6.20.155.1 (sources are uploaded) and set meta
Revert "linux: update dvbsky patch"

This reverts commit aee3ab6414bd5b8066417926d008071fa2a4d7d8.

as requested (again) from Silicon Labs.
projects/*/linux/linux.*.conf: enable marvell pata

closes #2140
RPi: changed gpu_mem to 100mb for 256mb RPis. fixes #1713
Merge pull request #2298 from stefansaraev/marvell

projects/*/linux/linux.*.conf: enable marvell pata
projects/*/linux/linux.*.conf: enable CONFIG_SATA_SIL24

closes #2161
Merge pull request #2286 from chewitt/wl-update

bcm_sta: update to 6.20.155.1
Merge pull request #2299 from jenkins101/RPi-gpu_mem

RPi: changed gpu_mem to 100mb for 256mb RPis. fixes #1713
libpng-host: install manually so libpng-config from target build will not be overwritten

Signed-off-by: Stephan Raue <stephan@openelec.tv>
libpng: force linking against libz

Signed-off-by: Stephan Raue <stephan@openelec.tv>