syscalls: Update the syscall table for Linux v6.12-rc5

Due to the addition of fstat & newfstatat to the LoongArch syscall ABI,
tests 38 and 55 have to be updated for the changed syscall numbers.

As for the PNR additions, normally they are allocated alphabetically for
the syscalls introduced between updates of the table, but in the v2.5
release branch -10245 is already assigned to map_shadow_stack in
commit 53267af3 ("all: update the syscall table for Linux v6.7-rc3").
While the map_shadow_stack syscall is in fact available across all
architectures, for consistency with v2.5.5 and later it is kept in the
same position in this update.

Signed-off-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Paul Moore <paul@paul-moore.com>