ARM: 7137/1: Fix error upon adding LL debug

Upon adding new board LL debug support, if the resultant code
addition would not cause PC relative offset of "hexbuf" from
"adr r2, hexbuf" (+2) instruction to be representable in a
shifted 8-bit value (hence indirectly putting higher aligment
requirement on larger offsets), following error occurs,

arch/arm/kernel/debug.S: Assembler messages:
arch/arm/kernel/debug.S:138: Error: invalid constant (428) after fixup

Fix it by bringing "hexbuf" closer so that "adr"
can have the offset.

Signed-off-by: Afzal Mohammed <afzal@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>