socfpga: Enable optimized inlining on stratix10

Enable the new CONFIG_OPTIMIZE_INLINING and CONFIG_SPL_OPTIMIZE_INLINING
options for this platform.  With gcc-9.2 from kernel.org this saves us
1784 bytes in U-Boot and 80 bytes in SPL.

Cc: Chin-Liang See <chin.liang.see@intel.com>
Cc: Dinh Nguyen <dinh.nguyen@intel.com>
Signed-off-by: Tom Rini <trini@konsulko.com>