[ARM] 4530/1: MXC: fix elf_hwcap compile breakage as in iop13xx

MXC needs the same change as IOP.  See [ARM] 4494/1
or commit 7dea1b2006

An undefined reference to elf_hwcap prevents linkage, due
to changes made by f884b1cf57
and d1cbbd6b41

Removing processor.h removes the extern definition of
elf_hwcap, which fixes the link issue, but forgets cpu_relax().
So, instead, we'll call barrier() directly.

Cc: Lennert Buytenhek <kernel@wantstofly.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Ross Wille <wille@freescale.com>
Signed-off-by: Quinn Jensen <quinn.jensen@freescale.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

include/asm-arm/arch-mxc/uncompress.h

@@ -26,7 +26,6 @@
 #define __MXC_BOOT_UNCOMPRESS
 
 #include <asm/hardware.h>
-#include <asm/processor.h>
 
 #define UART(x) (*(volatile unsigned long *)(serial_port + (x)))
 
@@ -62,7 +61,7 @@ static void putc(int ch)
 	}
 
 	while (!(UART(USR2) & USR2_TXFE))
-		cpu_relax();
+		barrier();
 
 	UART(TXR) = ch;
 }