clk: davinci: psc-da850: remove the 'davinci_nand.0" lookup

Since commit a8e3923a ("mtd: rawnand: davinci: don't acquire and
enable clock") we no longer acquire the aemif clock from the davinci
nand driver - we only do it from the ti-aemif driver. Remove the nand
entry from the psc lookup table.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: David Lechner <david@lechnology.com>
Signed-off-by: David Lechner <david@lechnology.com>