package/libgcrypt: add upstream patch to add pkg-config file

package/libgcrypt: add upstream patch to add pkg-config file

libgrypt provides a config file `libgcrypt-config`. After the version
bump to 1.8.4 upstream added a pkg-config file as well [1].

Using the pkg-config file is preferred over using the package provided
config file. For example, the Meson build system requires that for every
special config file an entry is added to the `[binary]` section in the
cross-compilation.conf file, otherwise it will use the config file found
in `PATH`. This is bad when cross-compiling as `PATH` will include
pathes to the host and therefore Meson will wrongly use the host config
file.

To simplify using libgcrypt for packages using the meson infrastructure
lets add the pkg-config file.

Note, that the additional upstream patch 0003 fixes a typo in the pkg-config
file.

[1] https://github.com/gpg/libgcrypt/commit/97194b422bc89a6137f4e218d4cdee118c63e96e

Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>