package/openocd: fix -fno-common build failure

Added upstream patch for fixing build failure when using GCC10 as a host
compiler (-fno-common is now default)

Fixes:
http://autobuild.buildroot.org/results/0fc/0fcb11a40bcff78e8084335114af390d2fac31e1



Cc: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Heiko Thiery <heiko.thiery@gmail.com>
Tested-by: Yann E. MORIN <yann.morin.1998@free.fr>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>