Revert "image.bbclass: allow overriding dependency on virtual/kernel:do_deploy"

Revert "image.bbclass: allow overriding dependency on virtual/kernel:do_deploy"

As pointed out in
https://lists.openembedded.org/g/openembedded-core/message/165058
https://lists.openembedded.org/g/openembedded-core/message/165216
this patch sets KERNELDEPLOYDEPEND but then uses KERNELDEPMODDEPEND.

Revert the changes since no one seems interested enough to fix it.
If someone wants this then make the variable name readable by
adding underscores where appropriate, for example by calling it
KERNEL_DEPLOY_DEPEND.

This reverts commit dcf9dfa4e6305786cd713aa28deda94a50bd6635.

Signed-off-by: Jacob Kroon <jacob.kroon@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>