According to AM572x DM SPRS953A, QSPI maximum bus speed can be 76.8MHz.
Therefore, increase the spi-max-frequency value of QSPI node to 76.8MHz
for DRA74 and DRA72 evm. This improves flash raw read speed by ~2MB/s.
Signed-off-by: NVignesh R <vigneshr@ti.com>
Signed-off-by: NTony Lindgren <tony@atomide.com>