staging/easycap: PAGE_SIZE is always defined

I'm not 100% sure, only 99.99% that PAGE_SIZE is always defined in
Linux. So there is no need to check for it.

Cc: Mike Thomas <rmthomas@sciolus.org>
Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru>
Acked-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/easycap/easycap.h

@@ -85,10 +85,6 @@
 #include <linux/videodev2.h>
 #include <linux/soundcard.h>
 
-#ifndef PAGE_SIZE
-#error "PAGE_SIZE not defined"
-#endif /* PAGE_SIZE */
-
 /*---------------------------------------------------------------------------*/
 /*  VENDOR, PRODUCT:  Syntek Semiconductor Co., Ltd
  *