build: restrict compiler options to supported architectures

build: restrict compiler options to supported architectures

For Linux we currently only support the following architectures:
'x86', 'x86_64', 'arm', 'arm-v7a', 'armeabi-v7a', 'arm64'
explicitly check for those architectures.

There is not option with v7a-hard in os_arch_map so it is not possible
to select this for target_arch, remove the options here because they
are unused.

Change-Id: I7078530bc2a89b88c7049cc53e8bb3fbe5d75ca8
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Reviewed-on: https://gerrit.iotivity.org/gerrit/15433
Reviewed-by: Phil Coval <philippe.coval@osg.samsung.com>
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: Dan Mihai <Daniel.Mihai@microsoft.com>