common/meson.build: fix required headers missing failure

[parr0tr1ver]

It fails occasionally with missing generated header files:

| ../git/common/asn1.c:42:10: fatal error: openssl.asn.h: No such file or directory | 42 | #include "openssl.asn.h" | | ^~~~~~~ | compilation terminated.

According to meson manual page:

https://mesonbuild.com/Wrap-best-practices-and-tips.html#declare-generated-headers-explicitly

'asn_h_dep' should be a dependency of static_library target 'libp11_asn1' to make sure that required header files generated before compile common/asn1.c.

[coveralls]

coverage: 69.477% (-0.03%) from 69.503% when pulling 8203fdfc46d319b57b44aaa8f31edf16230d3733 on parr0tr1ver:master into 90bc380385fe2d0c79d1853c7607607e932aeddd on p11-glue:master.

[quaresmajose]

I've also been seeing this problem recurrently recently in some of my builds. Thanks for the fix.