[packages] dhcpcd : fix compile for OMAP

v2:
-add CFLAGS to configure test

configure test failed silently on OMAP because of missing CFLAGS (-mfloat-abi=hard) with
../arm-openwrt-linux-uclibcgnueabi/bin/ld: error: _getifaddrs uses VFP register arguments

Signed-off-by: Dirk Neukirchen <dirkneukirchen@web.de>