linux-ltd: bump kernel to commit 6372c78
linux-ltd: bump kernel to commit 6372c78

Updates including v4.11.2 and wl1835 bluetooth support for beaglebone
black wireless.

Signed-off-by: Ricardo Salveti <6fd42f733b6586c555e01d4ff3116fc7e73e7330@linaro.org>

linaro-technologies/meta-ltd