package/libffi: bump version to 3.4.6

package/libffi: bump version to 3.4.6

Removed patch 0001 and instead added new configure option
--disable-multi-os-directory which was added upstream:
https://github.com/libffi/libffi/commit/877ea9bf9ac2c98cb858c12f5a6aeeec13cf978f

Removed patch 0003 due to various upstream fixes for mips soft-float
support since its addition in 2016:
https://github.com/libffi/libffi/commits/master/src/mips

Renumbered remaining patch.

Updated license hash due to copyright year bump:
https://github.com/libffi/libffi/commit/91739a1a912476adbf1e0e4dcb091b9a2c5007d9

Signed-off-by: Bernd Kuhls <[email protected]>
Reviewed-by: Adam Duskett <[email protected]>
Tested-by: Adam Duskett <[email protected]>
[[email protected]: fix check-package]
Signed-off-by: Yann E. MORIN <[email protected]>