Eliminate PowerPC libcpu/page.h

Started to eliminate warnings and then realized that only one one-line
macro in the file was used by a few files. The rest of the file was
was not needed. Eliminate the file.

Closes #3354.

c/src/lib/libbsp/powerpc/shared/bootloader/misc.c

@@ -19,11 +19,13 @@
 #include "bootldr.h"
 #include <libcpu/spr.h>
 #include "zlib.h"
-#include <libcpu/page.h>
 #include <libcpu/byteorder.h>
 #include <rtems/bspIo.h>
 #include <bsp.h>
 
+/* to align the pointer to the (next) page boundary */
+#define PAGE_ALIGN(addr)	(((addr)+PAGE_SIZE-1)&PAGE_MASK)
+
 SPR_RO(PPC_PVR)
 
 struct inode;