ata: use COMMAND_LINE_SIZE for ata_force_param_buf[] size

Use COMMAND_LINE_SIZE instead PAGE_SIZE for ata_force_param_buf[]
size as libata parameters buffer doesn't need to be bigger than
the command line buffer.

For many architectures this results in decreased libata-core.o
size (COMMAND_LINE_SIZE varies from 256 to 4096 while the minimum
PAGE_SIZE is 4096).

Code size savings on m68k arch using (modified) atari_defconfig:

   text    data     bss     dec     hex filename
before:
  41064    4413      40   45517    b1cd drivers/ata/libata-core.o
after:
  41064     573      40   41677    a2cd drivers/ata/libata-core.o

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/ata/libata-core.c

@@ -52,6 +52,7 @@
 #include <linux/leds.h>
 #include <linux/pm_runtime.h>
 #include <linux/platform_device.h>
+#include <asm/setup.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/libata.h>
@@ -106,7 +107,7 @@ struct ata_force_ent {
 static struct ata_force_ent *ata_force_tbl;
 static int ata_force_tbl_size;
 
-static char ata_force_param_buf[PAGE_SIZE] __initdata;
+static char ata_force_param_buf[COMMAND_LINE_SIZE] __initdata;
 /* param_buf is thrown away after initialization, disallow read */
 module_param_string(force, ata_force_param_buf, sizeof(ata_force_param_buf), 0);
 MODULE_PARM_DESC(force, "Force ATA configurations including cable type, link speed and transfer mode (see Documentation/admin-guide/kernel-parameters.rst for details)");