arm: Suppress tags about used cpu arch and extensions

arm: Suppress tags about used cpu arch and extensions

When all the codepaths using manually set .arch/.fpu code is
behind runtime detection, the elf attributes should be suppressed.

This allows tools to know that the final built binary doesn't
strictly require these extensions.

Signed-off-by: Martin Storsjö <martin@martin.st>
(cherry picked from commit dcae2e32f7d8a1ca5fb8c1e4aa81313be854dd73
and b77e335e441040a40fc6156b8e4a134745d10233)
Signed-off-by: Martin Storsjö <martin@martin.st>
(cherry picked from commit 9841654c158c80e9d525ba03754135d3f34e306e)

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>