libnspr: bump to version 4.12

Drop 0003-enable-internal-getproto-functions-for-musl.patch since it's
no longer required (tested via a flickcurl build with libnss against
mips-musl).

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>