[PATCH v5 3/4] mips: serial: Silence "unused variable" warning

[Philip Oberfichtner <pro@denx.de>]

Before this commit, mtmips_spl_serial_init() caused the following
warning:

  arch/mips/mach-mtmips/mt7628/serial.c:14:23: warning: unused variable ‘base’ [-Wunused-variable]
     14 |         void __iomem *base = ioremap_nocache(SYSCTL_BASE, SYSCTL_SIZE);
        |                       ^~~~

This happens whenever CONFIG_SPECIFY_CONSOLE_INDEX is unset, which leads
to an effectively empty function:

  void mtmips_spl_serial_init(void)
  {
	  void __iomem *base = ioremap_nocache(SYSCTL_BASE, SYSCTL_SIZE);
  }

Add the __maybe_unused attribute to silence this warning.

Signed-off-by: Philip Oberfichtner <pro@denx.de>
---

Notes:
    Changes in v5: none
    
    Changes in v4: new

 arch/mips/mach-mtmips/mt7620/serial.c     | 2 +-
 arch/mips/mach-mtmips/mt7621/spl/serial.c | 2 +-
 arch/mips/mach-mtmips/mt7628/serial.c     | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/mips/mach-mtmips/mt7620/serial.c b/arch/mips/mach-mtmips/mt7620/serial.c
index 35544b8537e..a6915865e27 100644
--- a/arch/mips/mach-mtmips/mt7620/serial.c
+++ b/arch/mips/mach-mtmips/mt7620/serial.c
@@ -24,7 +24,7 @@ void board_debug_uart_init(void)
 void mtmips_spl_serial_init(void)
 {
 #ifdef CONFIG_SPL_SERIAL
-	void __iomem *base = ioremap_nocache(SYSCTL_BASE, SYSCTL_SIZE);
+	void __iomem __maybe_unused *base = ioremap_nocache(SYSCTL_BASE, SYSCTL_SIZE);
 
 #if CONFIG_CONS_INDEX == 1
 	clrbits_32(base + SYSCTL_GPIOMODE_REG, UARTL_GPIO_MODE);
diff --git a/arch/mips/mach-mtmips/mt7621/spl/serial.c b/arch/mips/mach-mtmips/mt7621/spl/serial.c
index 5cf093a078a..3f600d778e7 100644
--- a/arch/mips/mach-mtmips/mt7621/spl/serial.c
+++ b/arch/mips/mach-mtmips/mt7621/spl/serial.c
@@ -11,7 +11,7 @@
 void mtmips_spl_serial_init(void)
 {
 #ifdef CONFIG_SPL_SERIAL
-	void __iomem *base = ioremap_nocache(SYSCTL_BASE, SYSCTL_SIZE);
+	void __iomem __maybe_unused *base = ioremap_nocache(SYSCTL_BASE, SYSCTL_SIZE);
 
 #if CONFIG_CONS_INDEX == 1
 	clrbits_32(base + SYSCTL_GPIOMODE_REG, UART1_MODE);
diff --git a/arch/mips/mach-mtmips/mt7628/serial.c b/arch/mips/mach-mtmips/mt7628/serial.c
index 11a2149e127..88d63f3825b 100644
--- a/arch/mips/mach-mtmips/mt7628/serial.c
+++ b/arch/mips/mach-mtmips/mt7628/serial.c
@@ -11,7 +11,7 @@
 void mtmips_spl_serial_init(void)
 {
 #ifdef CONFIG_SPL_SERIAL
-	void __iomem *base = ioremap_nocache(SYSCTL_BASE, SYSCTL_SIZE);
+	void __iomem __maybe_unused *base = ioremap_nocache(SYSCTL_BASE, SYSCTL_SIZE);
 
 #if CONFIG_CONS_INDEX == 1
 	clrbits_32(base + SYSCTL_GPIO_MODE1_REG, UART0_MODE_M);
-- 
2.39.5