[source] ar71xx: mach-rbspi: fix 74x164 support

[LEDE Commits]

mkresin pushed a commit to source.git, branch master:
https://git.lede-project.org/dfa29309887287d9f5bc9ef9748786525ad7ccee

commit dfa29309887287d9f5bc9ef9748786525ad7ccee
Author: Thibaut VARENE <hacks at slashdirt.org>
AuthorDate: Wed Nov 1 12:06:20 2017 +0100

    ar71xx: mach-rbspi: fix 74x164 support
    
    The platform data was missing the num_registers element which is now
    mandatory in linux 4.9
    
    Without this patch, the gpio probing would fail with:
    gpio gpiochip1: (74x164): tried to insert a GPIO chip with zero lines
    
    Fixes: #1106
    
    Tested-by: Robert Marko <robimarko at gmail.com>
    Signed-off-by: Thibaut VARENE <hacks at slashdirt.org>
---
 target/linux/ar71xx/files/arch/mips/ath79/mach-rbspi.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/target/linux/ar71xx/files/arch/mips/ath79/mach-rbspi.c b/target/linux/ar71xx/files/arch/mips/ath79/mach-rbspi.c
index 4cdc171..1045dfc 100644
--- a/target/linux/ar71xx/files/arch/mips/ath79/mach-rbspi.c
+++ b/target/linux/ar71xx/files/arch/mips/ath79/mach-rbspi.c
@@ -488,6 +488,7 @@ static struct gpio_keys_button rblhg_gpio_keys[] __initdata = {
 
 static struct gen_74x164_chip_platform_data rbspi_ssr_data = {
 	.base = RBSPI_SSR_GPIO_BASE,
+	.num_registers = 1,
 };
 
 /* the spi-ath79 driver can only natively handle CS0. Other CS are bit-banged */