Makefile: also consider -O, -Og and -Os when stripping flags

Makefile: also consider -O, -Og and -Os when stripping flags

gcc also supports -O, -Og and -Os as optimization flags.
They may be given on the make command-line by users.

For the calculation of LAPACK_NOOPT, all such flags should be considered.

Signed-off-by: Thomas De Schampheleire <thomas.de_schampheleire@nokia.com>
[Retrieved from:
https://git.buildroot.net/buildroot/tree/package/openblas/0003-Makefile-also-consider-Os-when-determining-LAPACK_NO.patch]
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>