pegasus: Use heap buffers for all register access

Allocating USB buffers on the stack is not portable, and no longer
works on x86_64 (with VMAP_STACK enabled as per default).

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
References: https://bugs.debian.org/852556
Reported-by: Lisandro Damián Nicanor Pérez Meyer <lisandro@debian.org>
Tested-by: Lisandro Damián Nicanor Pérez Meyer <lisandro@debian.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
static __u8 mii_phy_probe(pegasus_t *pegasus)
{
	int i;
	__u16 tmp;

	for (i = 0; i < 32; i++) {
		read_mii_word(pegasus, i, MII_BMSR, &tmp);
		if (tmp == 0 || tmp == 0xffff || (tmp & BMSR_MEDIA) == 0)
			continue;
		else
			return i;
	}

	return 0xff;
}

static __u8 mii_phy_probe(pegasus_t *pegasus)
{
	int i;
	__u16 tmp;

	for (i = 0; i < 32; i++) {
		read_mii_word(pegasus, i, MII_BMSR, &tmp);
		if (tmp == 0 || tmp == 0xffff || (tmp & BMSR_MEDIA) == 0)
			continue;
		else
			return i;
	}

	return 0xff;
}
