Building with the attached random configuration file,

drivers/spi/spi-bcm2835.c: In function 'chip_match_name':
drivers/spi/spi-bcm2835.c:356:21: error: dereferencing pointer to
incomplete type
  return !strcmp(chip->label, data);
                     ^
drivers/spi/spi-bcm2835.c: In function 'bcm2835_spi_setup':
drivers/spi/spi-bcm2835.c:382:2: error: implicit declaration of
function 'gpiochip_find' [-Werror=implicit-function-declaration]
  chip = gpiochip_find("pinctrl-bcm2835", chip_match_name);
  ^
drivers/spi/spi-bcm2835.c:382:7: warning: assignment makes pointer
from integer without a cast
  chip = gpiochip_find("pinctrl-bcm2835", chip_match_name);
       ^
drivers/spi/spi-bcm2835.c:387:21: error: dereferencing pointer to
incomplete type
  spi->cs_gpio = chip->base + 8 - spi->chip_select;
                     ^
drivers/spi/spi-bcm2835.c: In function 'chip_match_name':
drivers/spi/spi-bcm2835.c:357:1: warning: control reaches end of
non-void function [-Wreturn-type]
 }
 ^