In efi_capsule_write() the value 0 assigned to ret is never used.

Identified with cppcheck.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Link: https://lore.kernel.org/r/20200223205435.114915-1-xypron.glpk@gmx.deSigned-off-by: Ard Biesheuvel <ardb@kernel.org>