uboot-phytec

efi_loader: variable: attributes may not be changed if a variable exists

If a variable already exists, efi_set_variable() should not change
the variable's attributes. This patch enforces it.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>