pinmux: multiplexes across different functions of pins (mutually exclusive)
pinconf: configure electrical pins characteristics.
You can find pins/pads and their functions/alternate-functions in the APQ8016 datasheet.
This is what is configured by the pinmux entries.
pinmux, pinmux_cs and pinmux_gpio all define pinmuxing, they have different names because a device tree node path must be unique (you can not have same node name a same level). I assume pinmux is for MISO, MOSI, SCLK pin muxing and pinmux_cs for ‘chip select’.