ti-sysfw: update SYSFW images to 2019.12

Update AM65x and J721E SYSFW images to 2019.12

MD5 Checksums:
49c542d7af2903083fea45d721c158a7  ti-sysfw/ti-sci-firmware-am65x-gp.bin
807734a0870428d38b77bab708508b22  ti-sysfw/ti-sci-firmware-am65x-hs-cert.bin
94b3ec9529a050b529cf422f06740c59  ti-sysfw/ti-sci-firmware-am65x-hs-enc.bin
8f89bf037617e18b6de4ff127581dd33  ti-sysfw/ti-sci-firmware-j721e-gp.bin

Signed-off-by: Dan Murphy <dmurphy@ti.com>
Reviewed-by: Suman Anna <s-anna@ti.com>