UHD: Addressing Bug 466, as per Balint.
Do not set the mfloat-soft flag during the test for arm_neon.h.

Use the flags passed in from the toolchain. If this test runs on a hard-float
system, bad things happen.

Signed-off-by: Philip Balister <philip@opensdr.com>
Fix issue with "item32" registered size, Bug 466.