mtd: spi: renesas: Add R-Car Gen4 support

Support RPC SPI on R-Car Gen4 R8A779F0 S4 and R8A779G0 V4H SoCs.

Reviewed-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Signed-off-by: Hai Pham <hai.pham.ud@renesas.com>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
[Marek: Squash S4 and V4H patches, fix brackets around STRTIM2]
diff --git a/drivers/spi/renesas_rpc_spi.c b/drivers/spi/renesas_rpc_spi.c
index 07ff2d2..af1b368 100644
--- a/drivers/spi/renesas_rpc_spi.c
+++ b/drivers/spi/renesas_rpc_spi.c
@@ -140,6 +140,7 @@
 #define PRC_PHYCNT_EXDS		BIT(21)
 #define RPC_PHYCNT_OCT		BIT(20)
 #define RPC_PHYCNT_STRTIM(v)	(((v) & 0x7) << 15)
+#define RPC_PHYCNT_STRTIM2(v)	((((v) & 0x7) << 15) | (((v) & 0x8) << 24))
 #define RPC_PHYCNT_WBUF2	BIT(4)
 #define RPC_PHYCNT_WBUF		BIT(2)
 #define RPC_PHYCNT_MEM(v)	(((v) & 0x3) << 0)
@@ -212,9 +213,13 @@
 	 *       0: On H3 ES1.x (not supported in mainline U-Boot)
 	 *       6: On M3 ES1.x
 	 *       7: On other R-Car Gen3
+	 *      15: On R-Car Gen4
 	 */
 	if (cpu_type == RMOBILE_CPU_TYPE_R8A7796 && rmobile_get_cpu_rev_integer() == 1)
 		return RPC_PHYCNT_STRTIM(6);
+	else if (cpu_type == RMOBILE_CPU_TYPE_R8A779F0 ||
+		 cpu_type == RMOBILE_CPU_TYPE_R8A779G0)
+		return RPC_PHYCNT_STRTIM2(15);
 	else
 #endif
 		return RPC_PHYCNT_STRTIM(7);