smartweb: use SPL_TINY_MEMSET

The SPL code for smartweb is close to its limit and adding a few extra
instructions to SPL will cause it to overrun its sram allotement (thus
causing build failures).  To allow adding the 'spl_perform_fixups'
extension point to SPL, we'll enable SPL_TINY_MEMSET for smartweb.
Signed-off-by: NPhilipp Tomsich <philipp.tomsich@theobroma-systems.com>
Series-cc: trini

configs/smartweb_defconfig

@@ -54,4 +54,5 @@ CONFIG_USB_GADGET_DOWNLOAD=y
 CONFIG_USB_HOST_ETHER=y
 CONFIG_USB_ETHER_ASIX=y
 CONFIG_USB_ETHER_MCS7830=y
+CONFIG_SPL_TINY_MEMSET=y
 # CONFIG_EFI_LOADER is not set