build/core: Fix build errors

- Include task hooks only if they exists
- Fix typos

Change-Id: Ide3b1bd0bac050da5b96d1e9a0dabd55fbf675fe
Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>
--
 core/combo/arch/arm/armv7-a-neon.mk |    3 ++-
 core/combo/arch/arm/armv7-a.mk      |    3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)