boot/at91bootstrap: rename patches with the proper naming convention

boot/at91bootstrap: rename patches with the proper naming convention

As reported by check-package (by calling it directly):
use name <number>-<description>.patch

Output of:
make at91bootstrap-dirclean at91bootstrap-patch | grep 'Patching\|Applying'

Before:
>>> at91bootstrap 1.16 Patching
Applying at91bootstrap-1.16-eabi-fix.patch using patch:
Applying at91bootstrap-1.16-gcc-4.6.x-ldscript-fix.patch using patch:
Applying at91bootstrap-1.16-u-boot-relocation-fix.patch using patch:

After:
>>> at91bootstrap 1.16 Patching
Applying 0001-eabi-fix.patch using patch:
Applying 0002-gcc-4.6.x-ldscript-fix.patch using patch:
Applying 0003-u-boot-relocation-fix.patch using patch:

Signed-off-by: Ricardo Martincoski <[email protected]>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <[email protected]>