Change initdram() return type to phys_size_t

This patch changes the return type of initdram() from long int to phys_size_t.
This is required for a couple of reasons: long int limits the amount of dram
to 2GB, and u-boot in general is moving over to phys_size_t to represent the
size of physical memory.  phys_size_t is defined as an unsigned long on almost
all current platforms.

This patch *only* changes the return type of the initdram function (in
include/common.h, as well as in each board's implementation of initdram).  It
does not actually modify the code inside the function on any of the platforms;
platforms which wish to support more than 2GB of DRAM will need to modify
their initdram() function code.

Build tested with MAKEALL for ppc, arm, mips, mips-el. Booted on powerpc
MPC8641HPCN.

Signed-off-by: Becky Bruce <becky.bruce@freescale.com>

board/cpu86/cpu86.c

@@ -273,7 +273,7 @@ static long int try_init (volatile memctl8260_t * memctl, ulong sdmr,
 	return (size);
 }
 
-long int initdram (int board_type)
+phys_size_t initdram (int board_type)
 {
 	volatile immap_t *immap = (immap_t *) CFG_IMMR;
 	volatile memctl8260_t *memctl = &immap->im_memctl;