debian/rules: remove extra pkg-config

debian/rules: remove extra pkg-config

Not sure why the definition for deb_udevudevdir calls pkg-config with
the string "pkg-config" as its first argument.  Even more crazily, this
happens on Debian 12:

$ pkg-config --variable=udevdir udev
/lib/udev
$ pkg-config pkg-config --variable=udevdir udev
 /lib/udev

Note the leading space!  Given the sed script in the same definition,
I'm guessing that the extra space is NOT the desired behavior.

Cc: <linux-ext4@vger.kernel.org> # v1.47.1
Fixes: 288de9fb396811 ("debian: acknowledge NMU'ed changes to 1.47.0-2.4")
Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>