lib/crypto: sparc: Drop optimized MD5 code

lib/crypto: sparc: Drop optimized MD5 code

MD5 is obsolete.  Continuing to maintain architecture-optimized
implementations of MD5 is unnecessary and risky.  It diverts resources
from the modern algorithms that are actually important.

While there was demand for continuing to maintain the PowerPC optimized
MD5 code to accommodate userspace programs that are misusing AF_ALG
(https://lore.kernel.org/linux-crypto/c4191597-341d-4fd7-bc3d-13daf7666c41@csgroup.eu/),
no such demand has been seen for the SPARC optimized MD5 code.

Thus, let's drop it and focus effort on the more modern SHA algorithms,
which already have optimized code for SPARC.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20260326203341.60393-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>