usb: storage: Add check for kcalloc

As kcalloc may return NULL pointer, the return value should
be checked and return error if fails as same as the ones in
alauda_read_map.

Fixes: e80b0fad

 ("[PATCH] USB Storage: add alauda support")
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Link: https://lore.kernel.org/r/20221208110058.12983-1-jiasheng@iscas.ac.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>