fastboot: Change usb read request granularity to 32KB.
fastboot: Change usb read request granularity to 32KB.

By issuing transfers of 32KB at a time, we improve the download
performance.

Change-Id: Ib98b9c4ea94b652bea6fe6337ccdbf00c1aeacd5

Foxda-Tech/argo8-bootable-bootloader-lk,M1cha/android_bootable_bootloader_lk,M1cha/lktris,jsr-d10/android_bootable_bootloader_lk,chirayudesai/android_bootable_bootloader_lk,efidroid/lk,Redmi-dev/android_bootable_lk,t2m-foxfone/android_kernel_lk,M1cha/lktris,idor/dk50-bootable_bootloader_lk,idor/dk50-bootable_bootloader_lk,hanjae/lumiab0,idor/dk50-bootable_bootloader_lk,jbott/lk_gee,jsr-d10/android_bootable_bootloader_lk,Foxda-Tech/polaris-bootable-bootloader-lk,chirayudesai/android_bootable_bootloader_lk,hanjae/lumiab0,efidroid/lk,mozilla-b2g/kernel_lk,Foxda-Tech/polaris-bootable-bootloader-lk,M1cha/android_bootable_bootloader_lk,lg-devs/g2-bootloader,jbott/lk_gee,M1cha/android_bootable_bootloader_lk,hanjae/lumiab0,lg-devs/g2-bootloader,thornbirdblue/codeaurora_lk,Foxda-Tech/polaris-bootable-bootloader-lk,CanarySolutions/little-kernel,mozilla-b2g/kernel_lk,mozilla-b2g/fairphone2_kernel_lk,hanjae/lumiab0,t2m-foxfone/android_kernel_lk,detule/lk-g2-spr,detule/lk-g2-spr,M1cha/lktris,DooMLoRD/android_bootable_bootloader_lk,Foxda-Tech/argo8-bootable-bootloader-lk,CanarySolutions/little-kernel,CanarySolutions/little-kernel,Redmi-dev/android_bootable_lk,efidroid/lk,mozilla-b2g/kernel_lk,M1cha/android_bootable_bootloader_lk,t2m-foxfone/kernel_lk,t2m-foxfone/kernel_lk,thornbirdblue/codeaurora_lk,mozilla-b2g/fairphone2_kernel_lk,M1cha/lktris,M1cha/lktris,t2m-foxfone/android_kernel_lk,M1cha/android_bootable_bootloader_lk,DooMLoRD/android_bootable_bootloader_lk,detule/lk-g2-spr,DooMLoRD/android_bootable_bootloader_lk,detule/lk-g2-spr,t2m-foxfone/kernel_lk,idor/dk50-bootable_bootloader_lk,jbott/lk_gee,Foxda-Tech/argo8-bootable-bootloader-lk,jsr-d10/android_bootable_bootloader_lk,Foxda-Tech/argo8-bootable-bootloader-lk,jsr-d10/android_bootable_bootloader_lk,lg-devs/g2-bootloader,t2m-foxfone/kernel_lk,Redmi-dev/android_bootable_lk,lg-devs/g2-bootloader,idor/dk50-bootable_bootloader_lk,CanarySolutions/little-kernel,efidroid/lk,Foxda-Tech/polaris-bootable-bootloader-lk,DooMLoRD/android_bootable_bootloader_lk,mozilla-b2g/kernel_lk,detule/lk-g2-spr,t2m-foxfone/android_kernel_lk,thornbirdblue/codeaurora_lk,t2m-foxfone/android_kernel_lk,chirayudesai/android_bootable_bootloader_lk,jbott/lk_gee,M1cha/android_bootable_bootloader_lk,efidroid/lk,CanarySolutions/little-kernel,lg-devs/g2-bootloader,mozilla-b2g/fairphone2_kernel_lk,chirayudesai/android_bootable_bootloader_lk,Foxda-Tech/argo8-bootable-bootloader-lk,jbott/lk_gee,DooMLoRD/android_bootable_bootloader_lk,thornbirdblue/codeaurora_lk,Redmi-dev/android_bootable_lk,thornbirdblue/codeaurora_lk,hanjae/lumiab0,mozilla-b2g/fairphone2_kernel_lk,Redmi-dev/android_bootable_lk,jsr-d10/android_bootable_bootloader_lk,mozilla-b2g/fairphone2_kernel_lk,Foxda-Tech/polaris-bootable-bootloader-lk,t2m-foxfone/kernel_lk,mozilla-b2g/kernel_lk,chirayudesai/android_bootable_bootloader_lk