Add Infrastructure for SHGEMV

[Mousius]

This adds all the relevant bits and pieces to add a shgemv path as well as a future hgemm/hgemv path in a similar model to sb and b interfaces.

I've also fixed a few bits and pieces around shgemm which didn't build in a few situations.

[martin-frbg]

Thanks (pity about the duplicate work though)

[Mousius]

Thanks (pity about the duplicate work though)

Yeah, sorry about that, I was thinking about something else and got a bit carried away seeing what was missing here 🙀

[Mousius]

@martin-frbg I will leave hgemm/hgemm_batch/hgemm_strided and hgemv for you to make up for my over eagerness? 🙏

[ChipKerchner]

#5480

[ChipKerchner]

Getting these compiler warnings....

/proj_sw/user_dev/ckerchner/OpenBLAS/interface/gemm.c:593:76: warning: macro expansion producing 'defined' has undefined behavior [-Wexpansion-to-defined]
  593 | #if defined(GEMM_GEMV_FORWARD) && !defined(GEMM3M) && !defined(COMPLEX) && HFLOAT16_GEMM_GEMV_FORWARD && BFLOAT16_GEMM_GEMV_FORWARD
      |                                                                            ^
/proj_sw/user_dev/ckerchner/OpenBLAS/interface/gemm.c:591:38: note: expanded from macro 'HFLOAT16_GEMM_GEMV_FORWARD'

[ChipKerchner]

Should probably be done like this https://stackoverflow.com/questions/42074035/how-to-deal-with-clangs-3-9-wexpansion-to-defined-warning

#if (!defined(BFLOAT16) || (!defined(BGEMM) && defined(SBGEMM_GEMV_FORWARD)) || (defined(BGEMM) && defined(BGEMM_GEMV_FORWARD)))
#define BFLOAT16_GEMM_GEMV_FORWARD 1
#else
#define BFLOAT16_GEMM_GEMV_FORWARD 0
#endif
#if (!defined(HFLOAT16) || (!defined(HGEMM) && defined(SHGEMM_GEMV_FORWARD)) || (defined(HGEMM) && defined(HGEMM_GEMV_FORWARD)))
#define HFLOAT16_GEMM_GEMV_FORWARD 1
#else
#define HFLOAT16_GEMM_GEMV_FORWARD 0
#endif

[ChipKerchner]

I see a couple of places in test/Makefile where BUILD_BFLOAT16 has been added but I don't see the same for BUILD_HFLOAT16.

It looks like we have support for SBGEMM but not SHGEMM?

[ChipKerchner]

#5497