Mainline commit 4bdc0d676a64 ("remove ioremap_nocache and
devm_ioremap_nocache") in v5.6-rc1 removes ioremap_nocache() and replaces
all uses with ioremap(). As the commit message says that "ioremap has
provided non-cached semantics by default since the Linux 2.6", do the same
unconditionally.