kernel-resin.bbclass: Patch kernel using patch utility and not git
kernel-resin.bbclass: Patch kernel using patch utility and not git

There are cases were the kernel source is not a git repository. Trying to git
apply in such a case would silently proceed but without applying the patches.

Signed-off-by: Andrei Gherzan <8dc7c09356db0b1762fb140617d7375c0a5a4131@resin.io>

resin-os/meta-resin,resin-os/meta-resin,resin-os/meta-resin,resin-os/meta-resin