tty: rocket: Fix possible buffer overwrite on register_PCI

tty: rocket: Fix possible buffer overwrite on register_PCI

[ Upstream commit 0419056ec8fd01ddf5460d2dba0491aad22657dd ]

If number of isa and pci boards exceed NUM_BOARDS on the path
rp_init()->init_PCI()->register_PCI() then buffer overwrite occurs
in register_PCI() on assign rcktpt_io_addr[i].

The patch adds check on upper bound for index of registered
board in register_PCI.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Anton Vasilyev <vasilyev@ispras.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>