arm: Set NEW_PCIB in DEFAULTS rather than a subset of kernel configs

All other architectures set NEW_PCIB in DEFAULTS, with arm being the one
remaining straggler that only sets it for GENERIC and TEGRA124.
ARMADA38X and ARMADAXP contain device pci but don't set NEW_PCIB,
however GENERIC claims to support them and as part of that NEW_PCIB
support was added to mv_pci, so these configs are most likely just
stale. Other than NOTES that just leaves ALPINE as the one kernel with
PCI support not covered by GENERIC, but al_pci is supported by arm64
which enables NEW_PCIB, and it's just a generic_pcie_fdt_driver with
some fixup code to deal with quirks so should support PCI_RES_BUS just
fine. Therefore it is believed that all in-tree kernel configs support
NEW_PCIB in reality, and so let's take a step towards removing all the
non-NEW_PCIB code by having it always-on everywhere.

Reviewed by:	emaste, jhb, manu
MFC after:	1 month
Differential Revision:	https://reviews.freebsd.org/D43806

sys/arm/conf/DEFAULTS

@@ -6,4 +6,6 @@ device		mem
 
 # Default congestion control algorithm
 options 	CC_CUBIC		# include CUBIC congestion control
+
+options 	NEW_PCIB
 options 	INTRNG			# All arm systems use INTRNG these days

sys/arm/conf/GENERIC

@@ -98,7 +98,6 @@ device		ahci			# AHCI-compatible SATA controllers
 #device		ata			# Legacy ATA/SATA controllers
 
 # PCI
-options 	NEW_PCIB
 device		pci
 device		pci_host_generic
 

sys/arm/conf/TEGRA124

@@ -111,7 +111,6 @@ device		ums			# USB mouse
 #device		wlan_amrr		# AMRR transmit rate control algorithm
 
 # PCI
-options 	NEW_PCIB
 device		pci
 
 # PCI Ethernet NICs that use the common MII bus controller code.