package/flashrom: fix build on riscv

Retrieve an upstream patch to fix build with riscv as it fails to
retrieve architecture due to "Use sigaction with SA_RESTART instead"
being caught before riscv:

exec: export LC_ALL=C ; { /home/fabrice/buildroot/output/host/bin/riscv32-linux-gcc -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -E archtest.c 2>/dev/null | grep -v ^# | grep ' | cut -f 2 -d' ; }
Use sigaction with SA_RESTART instead
riscv

Fixes:
 - http://autobuild.buildroot.org/results/61ac6c9bfcd3bd9306aa49faf47b9f16e5abe846



Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>