aarch64, fix gdb with linux-custom

kernel_config_fragment

@@ -53,12 +53,15 @@ CONFIG_SCHED_TRACER=y
 CONFIG_STACK_TRACER=y
 CONFIG_TRACER_SNAPSHOT=y
 
-# x86
+## x86
+
 # https://stackoverflow.com/questions/20069620/print-kernels-page-table-entries
 # cat /sys/kernel/debug/kernel_page_tables
 CONFIG_X86_PTDUMP=y
 
-# LEDs. ARM only.
+## ARM
+
+# LEDs:
 #
 #     cd /sys/class/leds/versatile:0
 #     cat max_brightness
@@ -109,8 +112,6 @@ CONFIG_GPIOLIB=y
 CONFIG_GPIO_SYSFS=y
 CONFIG_GPIO_PL061=y
 
-#     run -a arm
-#
 # In target:
 #
 #     modprobe dummy-irq irq=34
@@ -125,3 +126,12 @@ CONFIG_GPIO_PL061=y
 #
 # The IRQ number 34 was found by via dmesg on a previous "insmod /platform_device.ko".
 CONFIG_DUMMY_IRQ=m
+
+## aarch64
+
+# For some reason not selected by default as it was for arm, and pci modules fail to build.
+# Not that we have PCI working on ARM anyways.
+CONFIG_PCI=y
+
+# Like CONFIG_X86_PTDUMP for ARM.
+CONFIG_ARM64_PTDUMP=y