ARM: EXYNOS: Do not resume l2x0 if not enabled before suspend

Trying to resume l2x0 if it was not enabled before suspend leads to
system crash. This patch prevents this by checking if l2x0_regs_phys is
a valid pointer to l2x0 context data saved on initialization.
Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

arch/arm/plat-samsung/s5p-sleep.S

@@ -59,13 +59,15 @@ ENTRY(s3c_cpu_resume)
 	and	r0, r0, r1
 	ldr	r1, =CPU_CORTEX_A9
 	cmp	r0, r1
-	bne	resume_l2on
+	bne	skip_l2_resume
 	adr	r0, l2x0_regs_phys
 	ldr	r0, [r0]
+	cmp	r0, #0
+	beq	skip_l2_resume
 	ldr	r1, [r0, #L2X0_R_PHY_BASE]
 	ldr	r2, [r1, #L2X0_CTRL]
 	tst	r2, #0x1
-	bne	resume_l2on
+	bne	skip_l2_resume
 	ldr	r2, [r0, #L2X0_R_AUX_CTRL]
 	str	r2, [r1, #L2X0_AUX_CTRL]
 	ldr	r2, [r0, #L2X0_R_TAG_LATENCY]
@@ -78,7 +80,7 @@ ENTRY(s3c_cpu_resume)
 	str	r2, [r1, #L2X0_POWER_CTRL]
 	mov	r2, #1
 	str	r2, [r1, #L2X0_CTRL]
-resume_l2on:
+skip_l2_resume:
 #endif
 	b	cpu_resume
 ENDPROC(s3c_cpu_resume)