hyperscan: fix broken build w/ external toolchain

hyperscan: fix broken build w/ external toolchain

If building with the project external toolchain, the gcc check
fails to set the correct value for TUNE_FLAG to allow the min
supported SSSE3 compiler support test to pass.  This patch hacks
the file to set to the correct value.

Links to upstream bug reports:
https://github.com/openwrt/openwrt/issues/15216
https://github.com/intel/hyperscan/issues/431

Build system: x86/64 (build system toolchain and x86/64 w/ external toolchain (18-Apr-2024 snapshot)
Build-tested: x86/64/AMD Cezanne
Run-tested: x86/64/AMD Cezanne

Signed-off-by: John Audia <therealgraysky@proton.me>