scripts/gdb: fix interrupts display after MCP on x86

The text line would not be appended to as it should have, it should have
been a '+=' but ended up being a '==', fix that.

Link: https://lkml.kernel.org/r/20250623164153.746359-1-florian.fainelli@broadcom.com
Fixes: b0969d7 ("scripts/gdb: print interrupts")
Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: ffainelli

scripts/gdb/linux/interrupts.py

@@ -142,7 +142,7 @@ def x86_show_interupts(prec):
 
     if constants.LX_CONFIG_X86_MCE:
         text += x86_show_mce(prec, "&mce_exception_count", "MCE", "Machine check exceptions")
-        text == x86_show_mce(prec, "&mce_poll_count", "MCP", "Machine check polls")
+        text += x86_show_mce(prec, "&mce_poll_count", "MCP", "Machine check polls")
 
     text += show_irq_err_count(prec)