PCI: endpoint: Select CRC32 to fix test build error

The PCI endpoint test driver uses crc32_le() so it should select
CRC32. Fixes this build error (when CRC32=m):

drivers/built-in.o: In function `pci_epf_test_cmd_handler':
pci-epf-test.c:(.text+0x2d98d): undefined reference to `crc32_le'

Fixes: 349e7a85b25f ("PCI: endpoint: functions: Add an EP function to test PCI")
Reported-by: kbuild test robot <[e-mail]>
Signed-off-by: Randy Dunlap <[e-mail]>
Signed-off-by: Bjorn Helgaas <[e-mail]>
Acked-by: Kishon Vijay Abraham I <[e-mail]>

drivers/pci/endpoint/functions/Kconfig

···
 config PCI_EPF_TEST
 	tristate "PCI Endpoint Test driver"
 	depends on PCI_ENDPOINT
+	select CRC32
 	help
 	   Enable this configuration option to enable the test driver
 	   for PCI Endpoint.