jpeg encode and decode

[weilian1977]

K210 chip support hardware jpeg encode and decode？

[kendryte747]

K210 have no hardware jpeg codec.

[weilian1977]

software jpeg encode and decode？encode and decode speed？

[kendryte747]

Use stb_image decode this jpeg used 29914 us.

Use stb_image_write encode camera image such as this jpeg used 42481 us.(quality is 90)

CPU Freq is 400Mhz.