linux: add option to include git submodules

Some kernel users find it useful to store submodules in the kernel
source tree for cross source trees definitions. Add option to download
these submodules.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

linux/Config.in

@@ -126,6 +126,12 @@ config BR2_LINUX_KERNEL_CUSTOM_REPO_VERSION
 
 endif
 
+config BR2_LINUX_KERNEL_CUSTOM_REPO_GIT_SUBMODULES
+	bool "Download also git submodules"
+	depends on BR2_LINUX_KERNEL_CUSTOM_GIT
+	help
+	  Include git submodules in the kernel source tree.
+
 config BR2_LINUX_KERNEL_VERSION
 	string
 	default "6.8.6" if BR2_LINUX_KERNEL_LATEST_VERSION

linux/linux.mk

@@ -24,6 +24,9 @@ LINUX_SOURCE = $(notdir $(LINUX_TARBALL))
 else ifeq ($(BR2_LINUX_KERNEL_CUSTOM_GIT),y)
 LINUX_SITE = $(call qstrip,$(BR2_LINUX_KERNEL_CUSTOM_REPO_URL))
 LINUX_SITE_METHOD = git
+ifeq ($(BR2_LINUX_KERNEL_CUSTOM_REPO_GIT_SUBMODULES),y)
+LINUX_GIT_SUBMODULES = YES
+endif
 else ifeq ($(BR2_LINUX_KERNEL_CUSTOM_HG),y)
 LINUX_SITE = $(call qstrip,$(BR2_LINUX_KERNEL_CUSTOM_REPO_URL))
 LINUX_SITE_METHOD = hg