Revert "libstagefright: Don't enable QCOM_LEGACY_MMPARSER with TARGET_QCOM_LEGACY_OMX"

This reverts commit 000ce22848ba8b4917f90a3961f0a58a224e766b.
libstagefright: Give LEGACY_MMPARSER its own board option; fix spacing

HTC 7x27 devices can't use LEGACY_MMPARSER, but still need LEGACY_OMX

Change-Id: I618977a8812d1f9a248e437a3fc563109259a60f