libftdi : fix build error

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- using cmake to find libusb
- fix header location

fixes #13258

Signed-off-by: Dirk Neukirchen <dirkneukirchen@web.de>


git-svn-id: svn://svn.openwrt.org/openwrt/packages@39519 3c298f89-4303-0410-b956-a3cf2f4a3e73
libftdi: fix pkgconfig support by installing .pc into staging dir

Signed-off-by: Alexander Couzens <lynxis@fe80.eu>


git-svn-id: svn://svn.openwrt.org/openwrt/packages@39520 3c298f89-4303-0410-b956-a3cf2f4a3e73