sysutils/cpu-microcode-amd: Update to 2025-07-29 snapshot

This snapshot updates firmware for processor family 19h and adds
firmware for processor family 1ah.

Linux firmware commit:
https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/commit/amd-ucode?id=3768c184de68a85b9df6697e7f93a2f61de90a99

Sponsored by: The FreeBSD Foundation