MN10300: Give correct size when reserving interrupt vector table

Give the correct size when reserving the interrupt vector table.  It should be
a page not a single byte.

Signed-off-by: Akira Takeuchi <takeuchi.akr@jp.panasonic.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>