ccid: fix build with pkgconf 1.5.3

ccid: fix build with pkgconf 1.5.3

Since the bump to 1.5.3, pkgconf prepends the sysroot to all absolute
paths found in the .pc file. This is correct when the paths refer to
something in STAGING_DIR (e.g. libdir, includedir), but not when it
refers to something used for the target.

ccid uses the usbdropdir variable from libpcsclite.pc to decide where to
install things. Since DESTDIR is prepended to the install destination,
this will end up in the wrong location.

Until a better solution is found in pkgconf, pass the usbdropdir to use
explicitly instead of relying on libpcsclite.pc.

Fixes:
 - http://autobuild.buildroot.org/results/4d4c1ba7f5d00d1b927ac01ef9851468abfbdff2

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>