coverage: add support for GCC 15

GCC 15 (with commit "Add prime path coverage to gcc/gcov") added a
new, tenth counter. Reflect this in gcc_4_7.c.

Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com>
Acked-by: Jan Beulich <jbeulich@suse.com>

xen/common/coverage/gcc_4_7.c

@@ -30,8 +30,10 @@
 #define GCOV_COUNTERS 9
 #elif GCC_VERSION < 140000
 #define GCOV_COUNTERS 8
-#else
+#elif GCC_VERSION < 150000
 #define GCOV_COUNTERS 9
+#else
+#define GCOV_COUNTERS 10
 #endif
 
 #define GCOV_TAG_FUNCTION_LENGTH        3