fix(build): add forgotten BL_LDFLAGS to lto command line

as a result of missing BL_LDFLAGS '-Wl,--sort-section=alignment' was
missing in link arguments for bl31.

Signed-off-by: Andrey Skvortsov <andrej.skvortzov@gmail.com>
Change-Id: I78878e49da21fdc565abb3072e4abaf9face49f4
1 file changed