Char: rocket, remove pci_read_config_dword(CLASS_REVISION)

We may use pdev->revision instead of reading pci config space directly, so
remove pci_read_config_dword invoking.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>