serial: allow COMPILE_TEST for some drivers

Some more serial drivers can be compile-tested under certain
circumstances (when building a specific architecture). So allow for
that.

This reduces the need of zillion mach/subarch-specific configs. And
since the 0day bot has only allmodconfig's for some archs, this
increases build coverage there too.

Note that cpm needs a minor update in the header, so that it drags in
at least some defines (CPM2 ones).
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220421101708.5640-8-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/Kconfig

@@ -783,7 +783,7 @@ config SERIAL_PMACZILOG_CONSOLE
 
 config SERIAL_CPM
 	tristate "CPM SCC/SMC serial port support"
-	depends on CPM2 || CPM1
+	depends on CPM2 || CPM1 || (PPC32 && COMPILE_TEST)
 	select SERIAL_CORE
 	help
 	  This driver supports the SCC and SMC serial ports on Motorola 
@@ -807,7 +807,7 @@ config SERIAL_CPM_CONSOLE
 
 config SERIAL_PIC32
 	tristate "Microchip PIC32 serial support"
-	depends on MACH_PIC32
+	depends on MACH_PIC32 || (MIPS && COMPILE_TEST)
 	select SERIAL_CORE
 	help
 	  If you have a PIC32, this driver supports the serial ports.
@@ -1247,7 +1247,7 @@ config SERIAL_XILINX_PS_UART_CONSOLE
 
 config SERIAL_AR933X
 	tristate "AR933X serial port support"
-	depends on HAVE_CLK && ATH79
+	depends on (HAVE_CLK && ATH79) || (MIPS && COMPILE_TEST)
 	select SERIAL_CORE
 	select SERIAL_MCTRL_GPIO if GPIOLIB
 	help

drivers/tty/serial/cpm_uart/cpm_uart.h

@@ -19,6 +19,8 @@ struct gpio_desc;
 #include "cpm_uart_cpm2.h"
 #elif defined(CONFIG_CPM1)
 #include "cpm_uart_cpm1.h"
+#elif defined(CONFIG_COMPILE_TEST)
+#include "cpm_uart_cpm2.h"
 #endif
 
 #define SERIAL_CPM_MAJOR	204