util-linux: add missing dynamic library dependency

util-linux: add missing dynamic library dependency

Commit f52af619185 (util-linux: add menu items for login utilities)
forgot to propagate the !BR2_STATIC_LIBS dependency of linux-pam to
BR2_PACKAGE_UTIL_LINUX_LOGIN. Fix this.

Fixes:
http://autobuild.buildroot.net/results/e47/e472891a656e40f33081d9a5db1b1b6d71c1389f/
http://autobuild.buildroot.net/results/9e4/9e443720ca247292ea612851962c611a9bcd3450/
http://autobuild.buildroot.net/results/88f/88f4cecd7e2844701b0e75279c112e37283fc7f9/

Cc: Carlos Santos <casantos@datacom.ind.br>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Reviewed-by: Carlos Santos <casantos@datacom.ind.br>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>