Kernel/LibC: Implement creat with open

This allows getting rid of unnecessary SYS_CREATE. Directory creation
still has its own syscall, but I could combine it with SYS_OPEN also.

kernel/include/kernel/Process.h

@@ -109,7 +109,6 @@ namespace Kernel
 		BAN::ErrorOr<long> sys_read(int fd, void* buffer, size_t count);
 		BAN::ErrorOr<long> sys_write(int fd, const void* buffer, size_t count);
 		BAN::ErrorOr<long> sys_access(const char* path, int amode);
-		BAN::ErrorOr<long> sys_create(const char*, mode_t);
 		BAN::ErrorOr<long> sys_create_dir(const char*, mode_t);
 		BAN::ErrorOr<long> sys_unlink(const char*);
 		BAN::ErrorOr<long> readlink_impl(BAN::RefPtr<Inode>, char* buffer, size_t bufsize);