cmd: boot: fix edl being shown when not supported

cmd: boot: fix edl being shown when not supported

edl is implemented in the sysreset_ops.request_arg callback of the
qcom-psci sysreset driver. That callback is only called from
sysreset_request_arg() which is compiled only when
CONFIG_SYSRESET_CMD_RESET_ARGS=y.

Therefore, only show the edl option if that symbol is enabled.

It is in a separate if block because any option but -w will only be
handled when CONFIG_SYSRESET_CMD_RESET_ARGS=y as seen with the
implementation in do_reset() in drivers/sysreset/sysreset-uclass.c.

Fixes: ef06c5d76ff4 ("cmd: boot: Add '-edl' option to reset command documentation")
Signed-off-by: Quentin Schulz <quentin.schulz@cherry.de>
Reviewed-by: Simon Glass <sjg@chromium.org>