m68k: atari: Make Atari ROM port I/O write macros return void

The macros implementing Atari ROM port I/O writes do not cast away their
output, unlike similar implementations for other I/O buses.
When they are combined using conditional expressions in the definitions of
outb() and friends, this triggers sparse warnings like:

    drivers/net/appletalk/cops.c:382:17: error: incompatible types in conditional expression (different base types):
    drivers/net/appletalk/cops.c:382:17:    unsigned char
    drivers/net/appletalk/cops.c:382:17:    void

Fix this by adding casts to "void".
Reported-by: Nkernel test robot <lkp@intel.com>
Reported-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: NGuenter Roeck <linux@roeck-us.net>
Reviewed-by: NMichael Schmitz <schmitzmic@gmail.com>
Link: https://lore.kernel.org/r/c15bedc83d90a14fffcd5b1b6bfb32b8a80282c5.1653057096.git.geert@linux-m68k.org

arch/m68k/include/asm/raw_io.h

@@ -80,14 +80,14 @@
 	({ u16 __v = le16_to_cpu(*(__force volatile u16 *) (addr)); __v; })
 
 #define rom_out_8(addr, b)	\
-	({u8 __maybe_unused __w, __v = (b);  u32 _addr = ((u32) (addr)); \
+	(void)({u8 __maybe_unused __w, __v = (b);  u32 _addr = ((u32) (addr)); \
 	__w = ((*(__force volatile u8 *)  ((_addr | 0x10000) + (__v<<1)))); })
 #define rom_out_be16(addr, w)	\
-	({u16 __maybe_unused __w, __v = (w); u32 _addr = ((u32) (addr)); \
+	(void)({u16 __maybe_unused __w, __v = (w); u32 _addr = ((u32) (addr)); \
 	__w = ((*(__force volatile u16 *) ((_addr & 0xFFFF0000UL) + ((__v & 0xFF)<<1)))); \
 	__w = ((*(__force volatile u16 *) ((_addr | 0x10000) + ((__v >> 8)<<1)))); })
 #define rom_out_le16(addr, w)	\
-	({u16 __maybe_unused __w, __v = (w); u32 _addr = ((u32) (addr)); \
+	(void)({u16 __maybe_unused __w, __v = (w); u32 _addr = ((u32) (addr)); \
 	__w = ((*(__force volatile u16 *) ((_addr & 0xFFFF0000UL) + ((__v >> 8)<<1)))); \
 	__w = ((*(__force volatile u16 *) ((_addr | 0x10000) + ((__v & 0xFF)<<1)))); })