Defining the two functions as 'static inline' and exporting them
leads to the interesting case where we can use the interface
from loadable modules, but not from built-in drivers, as shown
in this link failure:

vers/nvdimm/claim.o: In function `nsio_rw_bytes':
claim.c:(.text+0x1b8): undefined reference to `arch_invalidate_pmem'
drivers/nvdimm/pmem.o: In function `pmem_dax_flush':
pmem.c:(.text+0x11c): undefined reference to `arch_wb_cache_pmem'
drivers/nvdimm/pmem.o: In function `pmem_make_request':
pmem.c:(.text+0x5a4): undefined reference to `arch_invalidate_pmem'
pmem.c:(.text+0x650): undefined reference to `arch_invalidate_pmem'
pmem.c:(.text+0x6d4): undefined reference to `arch_invalidate_pmem'

This removes the bogus 'static inline'.

Fixes: d50e071f ("arm64: Implement pmem API support")
Acked-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>