ARM: dts: ls1021a: fix incorrect clock references

dtc warns about two 'clocks' properties that have an extraneous '1'
at the end:

arch/arm/boot/dts/ls1021a-qds.dtb: Warning (clocks_property): arch/arm/boot/dts/ls1021a-twr.dtb: Warning (clocks_property): Property 'clocks', cell 1 is not a phandle reference in /soc/i2c@2180000/mux@77/i2c@4/sgtl5000@2a
arch/arm/boot/dts/ls1021a-qds.dtb: Warning (clocks_property): Missing property '#clock-cells' in node /soc/interrupt-controller@1400000 or bad phandle (referred from /soc/i2c@2180000/mux@77/i2c@4/sgtl5000@2a:clocks[1])
Property 'clocks', cell 1 is not a phandle reference in /soc/i2c@2190000/sgtl5000@a
arch/arm/boot/dts/ls1021a-twr.dtb: Warning (clocks_property): Missing property '#clock-cells' in node /soc/interrupt-controller@1400000 or bad phandle (referred from /soc/i2c@2190000/sgtl5000@a:clocks[1])

The clocks that get referenced here are fixed-rate, so they do not
take any argument, and dtc interprets the next cell as a phandle, which
is invalid.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>