kernel: Add kmod-drm-ttm-helper

kernel: Add kmod-drm-ttm-helper

Add a package for drm_ttm_helper.ko. CONFIG_DRM_TTM_HELPER is compiled
into the kernel on armvirt/64, x86/64, x86/generic and x86/legacy
because also some DRM drivers are compiled into the kernel. On x86/geode
it is not compiled into the kernel, but kmod-drm-amdgpu and
kmod-drm-radeon depend on it.

This fixes the x86/geode build.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>