u-boot-qoriq: Add host compiler flags

u-boot-qoriq: Add host compiler flags

U-Boot will compile its own tools during the build, with specific
configurations (aka when CONFIG_FIT_SIGNATURE is enabled) the host tools
require openssl. This patch adds 'openssl' as a PACKAGECONFIG that
enables the use of openssl-native as a dependency and also adds the
HOSTCC flags that U-Boot uses when compiling the host tools.

(From OE-Core rev: 7d0edf5d04fba0b642bfb08a1de28fbc8e480209)

Signed-off-by: Ting Liu <ting.liu@nxp.com>
Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>