add TTY_TERMINAL build option for ARM BDS

add TTY_TERMINAL build option for ARM BDS

Enable selecting the TtyTerminal type for the ARM BDS build of QEMU using
the TTY_TERMINAL define.
Convert INTEL_BDS define to check for value (!if) rather than just definition
(!ifdef) to allow setting of either value on command line.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Roy Franz <roy.franz@linaro.org>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@17899 6f19259b-4bc3-4df7-8a09-765794883524