s390: Implement __iowrite32_copy()

It is trivial to implement an inline to do this, so provide it in the s390
headers. Like the 64 bit version it should just invoke zpci_memcpy_toio()
with the correct size.

Link: https://lore.kernel.org/r/2-v3-1893cd8b9369+1925-mlx5_arm_wc_jgg@nvidia.comAcked-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

arch/s390/include/asm/io.h

@@ -73,6 +73,14 @@ static inline void ioport_unmap(void __iomem *p)
 #define __raw_writel	zpci_write_u32
 #define __raw_writeq	zpci_write_u64
 
+/* combine single writes by using store-block insn */
+static inline void __iowrite32_copy(void __iomem *to, const void *from,
+				    size_t count)
+{
+	zpci_memcpy_toio(to, from, count * 4);
+}
+#define __iowrite32_copy __iowrite32_copy
+
 #endif /* CONFIG_PCI */
 
 #include <asm-generic/io.h>