fbdev: sm501fb: Convert sysfs snprintf to sysfs_emit

Follow the advice of the Documentation/filesystems/sysfs.rst
and show() should only use sysfs_emit() or sysfs_emit_at()
when formatting the value to be returned to user space.

Signed-off-by: Xuezhi Zhang <[e-mail]>
Signed-off-by: Helge Deller <[e-mail]>

drivers/video/fbdev/sm501fb.c

···
 	ctrl = smc501_readl(info->regs + SM501_DC_CRT_CONTROL);
 	ctrl &= SM501_DC_CRT_CONTROL_SEL;
 
-	return snprintf(buf, PAGE_SIZE, "%s\n", ctrl ? "crt" : "panel");
+	return sysfs_emit(buf, "%s\n", ctrl ? "crt" : "panel");
 }
 
 /* sm501fb_crtsrc_show