package/ficl: fix musl static build

Pass LDFLAGS to avoid the following musl static build failure raised
since the addition of the package in commit
814911ae:

/home/autobuild/autobuild/instance-5/output-1/host/lib/gcc/sh4eb-buildroot-linux-musl/11.3.0/../../../../sh4eb-buildroot-linux-musl/bin/ld: /home/autobuild/autobuild/instance-5/output-1/host/lib/gcc/sh4eb-buildroot-linux-musl/11.3.0/libgcc.a(unwind-dw2.o): in function `size_of_encoded_value':
/home/autobuild/autobuild/instance-5/output-1/build/host-gcc-final-11.3.0/build/sh4eb-buildroot-linux-musl/libgcc/../../../libgcc/unwind-pe.h:89: undefined reference to `abort'

Fixes:
 - http://autobuild.buildroot.org/results/bf041723ed813746c61892262630a3ac2bc43b14



Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>