[POWERPC] Use cache-inhibited large page bit from firmware

Discussions with firmware architects have confirmed that the bit in
the ibm,pa-features property that indicates support for
cache-inhibited large (>= 64kB) page mappings does in fact mean that
the hypervisor allows 64kB mappings to I/O devices.

Thus we can now enable the code that tests that bit and sets our
CPU_FTR_CI_LARGE_PAGE feature bit.

Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/kernel/prom.c

@@ -531,10 +531,7 @@ static struct ibm_pa_feature {
 	{CPU_FTR_CTRL, 0,		0, 3, 0},
 	{CPU_FTR_NOEXECUTE, 0,		0, 6, 0},
 	{CPU_FTR_NODSISRALIGN, 0,	1, 1, 1},
-#if 0
-	/* put this back once we know how to test if firmware does 64k IO */
 	{CPU_FTR_CI_LARGE_PAGE, 0,	1, 2, 0},
-#endif
 	{CPU_FTR_REAL_LE, PPC_FEATURE_TRUE_LE, 5, 0, 0},
 };