drivers: display: st7796s: use mipi_dbi_configure_te API

Use the mipi_dbi_configure_te API within the st7796s display driver.
If the MIPI DBI controller supports the tearing enable signal, then
configure the ST7796S to output the TE line signal.

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