mainboard/google/kahlee: Pass oscout system clk to da7219

Using da7219 mclk-name property, oscout system clock is linked
to da7219 mclk. da7219 then handles enabling/disabling of the clk.

BUG=b:74570989
TEST=Tested clock enable/disable in kernel driver

Change-Id: I298b0ce5d2c40daadeb5d68f9cb595a965272021
Signed-off-by: Akshu Agrawal <akshu.agrawal@amd.com>
Reviewed-on: https://review.coreboot.org/25920
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/mainboard/google/kahlee/variants/grunt/devicetree.cb

@@ -109,6 +109,7 @@ chip soc/amd/stoneyridge
 			register "adc_1bit_rpt" = "1"
 			register "micbias_lvl" = "2600"
 			register "mic_amp_in_sel" = ""diff""
+			register "mclk_name" = ""oscout1""
 			device i2c 1a on end
 		end
 		chip drivers/generic/max98357a