bnxt_en: Remove register mapping to support INTX

In legacy INTX mode, a register is mapped so that the INTX handler can
read it to determine if the NIC is the source of the interrupt.  This
and all the related macros are no longer needed now that INTX is no
longer supported.

Reviewed-by: Somnath Kotur <somnath.kotur@broadcom.com>
Reviewed-by: Hongguang Gao <hongguang.gao@broadcom.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Link: https://patch.msgid.link/20240828183235.128948-7-michael.chan@broadcom.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>