purism/librem13v1: Disable PCI Express AER capability

The Librem 13v1 does not seem to have working AER and this option
was needed and tested on the Librem 13v1. Without it, the linux
console gets spammed with AER errrors.

Change-Id: I13d0afa085b426920d7a946e6209f924ce29ae52
Signed-off-by: Youness Alaoui <youness.alaoui@puri.sm>

src/mainboard/purism/librem13v1/Kconfig

@@ -24,6 +24,9 @@ config DRIVERS_UART_8250IO
 config PCIEXP_L1_SUB_STATE
 	def_bool n
 
+config PCIEXP_AER
+	def_bool n
+
 config HAVE_IFD_BIN
 	bool
 	default n