usb: gadget: mbim: Do not return error 0 from read
usb: gadget: mbim: Do not return error 0 from read

Return 0 from mbim_read only as an indication
of reset command and cable disconnection.
For all failure cases return error code not equal 0.

CRs-Fixed: 429455
Change-Id: Ia921bf4cbda7647e6b04042943ed17759d8d9d9b
Signed-off-by: Anna Perel <c45864de69324ed72976f0f8987640a392ee613d@codeaurora.org>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas