ath79: remove unused patch

This patch ist not required, as it only has an effect in case the GPIO
descriptors supplied to num-cs are valid.

As this is not the case for ath79, this patch can safely be omitted. The
issue it tried to fix is actually fixed with
0054-spi-sync-up-initial-chipselect-state.

Signed-off-by: David Bauer <[email protected]>

target/linux/ath79/patches-5.10/0051-spi-ath79-always-call-chipselect-function.patch

@@ -1,21 +0,0 @@
-From: David Bauer <[email protected]>
-Date: Wed, 17 Feb 2021 02:44:55 +0100
-Subject: [PATCH] spi: ath79: always call chipselect function
-
-api-bitbang has to call the chipselect function on the ath79 SPI driver
-in order to communicate with the SPI slave device.
-
-Fixes commit 4a07b8bcd503 ("spi: bitbang: Make chipselect callback optional")
-
-Signed-off-by: David Bauer <[email protected]>
-
---- a/drivers/spi/spi-ath79.c
-+++ b/drivers/spi/spi-ath79.c
-@@ -152,6 +152,7 @@ static int ath79_spi_probe(struct platfo
- 
- 	master->use_gpio_descriptors = true;
- 	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);
-+	master->flags = SPI_MASTER_GPIO_SS;
- 
- 	sp->bitbang.master = master;
- 	sp->bitbang.chipselect = ath79_spi_chipselect;