ARM: arm920t: Allow use of 'gd' pointer from IRQ

This patch allows us to use the 'gd' pointer (and thus environment
and everything else associated with it) from interrupt context on
arm920t.

Signed-off-by: Harald Welte <laforge@openmoko.org>

cpu/arm920t/start.S

@@ -329,12 +329,12 @@ cpu_init_crit:
 	.macro	irq_save_user_regs
 	sub	sp, sp, #S_FRAME_SIZE
 	stmia	sp, {r0 - r12}			@ Calling r0-r12
-	add     r8, sp, #S_PC
-	stmdb   r8, {sp, lr}^                   @ Calling SP, LR
-	str     lr, [r8, #0]                    @ Save calling PC
+	add     r7, sp, #S_PC
+	stmdb   r7, {sp, lr}^                   @ Calling SP, LR
+	str     lr, [r7, #0]                    @ Save calling PC
 	mrs     r6, spsr
-	str     r6, [r8, #4]                    @ Save CPSR
-	str     r0, [r8, #8]                    @ Save OLD_R0
+	str     r6, [r7, #4]                    @ Save CPSR
+	str     r0, [r7, #8]                    @ Save OLD_R0
 	mov	r0, sp
 	.endm