staging: nvec: make use of devm_platform_ioremap_resource

fix below issue reported by coccicheck
drivers/staging//nvec/nvec.c:794:1-5: WARNING: Use
devm_platform_ioremap_resource for base

Signed-off-by: Hariprasad Kelam <hariprasad.kelam@gmail.com>
Acked-by: Marc Dietrich <marvin24@gmx.de>
Link: https://lore.kernel.org/r/1567935662-8006-1-git-send-email-hariprasad.kelam@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>