Imported from linux kernel v5.3:
 asymmetric-type.h with changes marked as __UBOOT__
 asymmetric_type.c with changes marked as __UBOOT__
 public_key.h with changes marked as __UBOOT__
 public_key.c with changes marked as __UBOOT__
Signed-off-by: NAKASHI Takahiro <takahiro.akashi@linaro.org>