xtensa: adjust boot parameters address when INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX is selected

The virtual address of boot parameters chain is passed to the kernel via
a2 register. Adjust it in case it is remapped during MMUv3 -> MMUv2
mapping change, i.e. when it is in the first 128M.

Also fix interpretation of initrd and FDT addresses passed in the boot
parameters: these are physical addresses.

Cc: stable@vger.kernel.org
Reported-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>

arch/xtensa/kernel/head.S

@@ -68,6 +68,15 @@ _SetupMMU:
 
 #ifdef CONFIG_INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
 	initialize_mmu
+#if defined(CONFIG_MMU) && XCHAL_HAVE_PTP_MMU && XCHAL_HAVE_SPANNING_WAY
+	rsr	a2, excsave1
+	movi	a3, 0x08000000
+	bgeu	a2, a3, 1f
+	movi	a3, 0xd0000000
+	add	a2, a2, a3
+	wsr	a2, excsave1
+1:
+#endif
 #endif
 	.end	no-absolute-literals