package/pkg-generic.mk: create directories before calling hooks

package/pkg-generic.mk: create directories before calling hooks

In commit 0e2be4db8ab01d479177a3a187c22525752195ae
("package/pkg-generic: make file list logic parallel build
compatible"), the logic to create the list of files installed by a
particular package was significantly reworked to be compatible with
top-level parallel build.

Before this commit, there was only a after-install step of listing the
files in HOST_DIR/TARGET_DIR/STAGING_DIR. But after this commit, we
now have a before-install logic and an after-install logic.

It turns out that when the before-install logic is called for the very
first host package, $(HOST_DIR) doesn't exist yet, and therefore the
cd $(2) fails, with an error message:

/bin/sh: line 0: cd: /home/thomas/buildroot/output/host: No such file or directory

In fact, $(HOST_DIR), $(STAGING_DIR), $(TARGET_DIR) and
$(BINARIES_DIR) are created by the make rules for host installation,
staging installation, target installation and images installation, but
*after* calling the step_start hooks.

So, we simply fix this problem by creating the directories *before*
calling the step_start hooks.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>