board: remove capsule update support in set_dfu_alt_info()

board: remove capsule update support in set_dfu_alt_info()

Now that capsule update sets the dfu_alt_info environment variable
explicitly, there is no need to support it in the set_dfu_alt_info()
function. Decouple SET_DFU_ALT_INFO from EFI_CAPSULE_FIRMWARE_FIT and
EFI_CAPSULE_FIRMWARE_RAW. For many boards, this was the only use of
set_dfu_alt_info() so remove the function entirely.

Fixes: a9e6f01a941f ("efi: Define set_dfu_alt_info() for boards with UEFI capsule update enabled")

Signed-off-by: Jonathan Humphreys <j-humphreys@ti.com>
Signed-off-by: Michal Simek <michal.simek@amd.com>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org> # for board/libre-computer/*
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Reviewed-by: Wadim Egorov <w.egorov@phytec.de> # for