ixgbe: make register maps const
ixgbe: make register maps const

These are const data structures, just put them in txt segment
rather than having compiler emit code to set them up on the stack.

Signed-off-by: Stephen Hemminger <06fa905d7f2aaced6dc72e9511c71a2a51e8aead@networkplumber.org>
Acked-by: Bruce Richardson <66b9e8e8fbd5e9f41f91b0af050876182ce9d0e4@intel.com>
Acked-by: Changchun Ouyang <593bf1f161e79772915ea885e47cf0e95f4498c0@intel.com>

phermansson/dpdk,phermansson/dpdk,phermansson/dpdk,phermansson/dpdk