serial: cpm_uart: Refactor cpm_uart_allocbuf()/cpm_uart_freebuf()

cpm_uart_freebuf() is identical for CPM1 and CPM2.

cpm_uart_allocbuf() only has a small difference between CPM1 and CPM2
as shown below:

CPM1:
	if (is_con) {
		/* was hostalloc but changed cause it blows away the */
		/* large tlb mapping when pinning the kernel area    */
		mem_addr = (u8 *) cpm_dpram_addr(cpm_dpalloc(memsz, 8));
		dma_addr = (u32)cpm_dpram_phys(mem_addr);
	} else
		mem_addr = dma_alloc_coherent(pinfo->port.dev, memsz, &dma_addr,
					      GFP_KERNEL);

CPM2:

	if (is_con) {
		mem_addr = kzalloc(memsz, GFP_NOWAIT);
		dma_addr = virt_to_bus(mem_addr);
	}
	else
		mem_addr = dma_alloc_coherent(pinfo->port.dev, memsz, &dma_addr,
					      GFP_KERNEL);

Refactor this by using IS_ENABLED(CONFIG_CPM1)
and move both functions in cpm_uart_core.c as they are used only there.

While doing this, add the necessary casts to silence sparse for the CPM1
part. This is because a dma alloc is not expected to be an iomem but
for CPM1 as we use DPRAM this is seen as iomem.

Also replace calls to cpm_dpxxxx() by relevant cpm_muram_xxxx() calls.
This is needed at least for cpm_dpram_phys() which is only defined
for CPM1. Just do the same for all so that cpm_dpxxxx() macros can get
droped in the future.

To silence checkpatch, replace printk(KERN_ERR by pr_err( and display
function name instead of hard coded filename. Also replace
mem_addr == NULL by !mem_addr.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/606dfdd258a4f2f2882e2e189bef37526bb3b499.1691068700.git.christophe.leroy@csgroup.eu


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