Steps to reproduce:
1. Compile qtbase with examples for RPi4 board (eglfs platform)

2. Run `qopenglwidget` example on the board

Expect result:

Fonts convenient to read

Actual result:

Fonts are small and unreadable

Attachments:
eglfs.png - default settings output
eglfs.100.png - run with QT_FONT_DPI=100
qt.qpa.eglfs.kms.log - logs

As per logs, attached device has resolution of 1920x1080.

It's physical size is evaluated as 1280x720 mm (close to reality).

As per tests with QT_FONT_DPI default settings is like QT_FONT_DPI=40.

Here is my configure command:

./configure -release -opengl es2 -no-opengles3 -device linux-rasp-pi4-v3d-g++ \
        -device-option CROSS_COMPILE=/opt/rpi/rpi-gcc-8.3.0/bin/arm-linux-gnueabihf- \
        -sysroot /opt/rpi/sysroot/ -opensource -confirm-license -compile-examples -ccache -silent \
        -prefix /usr/local/qt5 -extprefix /opt/rpi/qt5 -hostprefix /opt/rpi/qt5