boards: shields: rk055hdmipi4ma0: increase DSI clock for RT1160

Increase target DSI clock frequency for the RT1160, as the DSI
peripheral requires a faster clock to account for the DSI packets that
must be sent outside of video mode frames.

This fix was previously applied for the RT1170, but is also needed for
the RT1160 SOC as they use the same DSI IP.

Fixes #78299

Signed-off-by: Daniel DeGrasse <daniel.degrasse@nxp.com>