scripts/gdb: mm: cast untyped symbols in x86_page_ops

The symbols phys_base, _text, and _end, used in x86_page_ops are either
defined in assembly or implicitly by the linker.  Thus, they lack type
information and cause a conversion error after gdb.parse_and_eval. 
Explicitly cast these expressions to unsigned long.

Link: https://lore.kernel.org/20260427142448.666117-2-illia@yshyn.com
Fixes: 55f8b45 ("scripts/gdb: implement x86_page_ops in mm.py")
Signed-off-by: Illia Ostapyshyn <illia@yshyn.com>
Cc: Florian Fainelli <florian.fainelli@broadcom.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.com>
Cc: Hao Li <hao.li@linux.dev>
Cc: Harry Yoo <harry@kernel.org>
Cc: Seongjun Hong <hsj0512@snu.ac.kr>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: iostapyshyn

scripts/gdb/linux/mm.py

@@ -40,11 +40,11 @@ def __init__(self):
 
         self.PAGE_OFFSET = int(gdb.parse_and_eval("page_offset_base"))
         self.VMEMMAP_START = int(gdb.parse_and_eval("vmemmap_base"))
-        self.PHYS_BASE = int(gdb.parse_and_eval("phys_base"))
+        self.PHYS_BASE = int(gdb.parse_and_eval("(unsigned long) phys_base"))
         self.START_KERNEL_map = 0xffffffff80000000
 
-        self.KERNEL_START = gdb.parse_and_eval("_text")
-        self.KERNEL_END = gdb.parse_and_eval("_end")
+        self.KERNEL_START = gdb.parse_and_eval("(unsigned long) &_text")
+        self.KERNEL_END = gdb.parse_and_eval("(unsigned long) &_end")
 
         self.VMALLOC_START = int(gdb.parse_and_eval("vmalloc_base"))
         if self.VMALLOC_START == 0xffffc90000000000: