ArmPkg/CompilerIntrinsicsLib: Reverse the order of the 'ldrb' instructions in __aeabi...

ArmPkg/CompilerIntrinsicsLib: Reverse the order of the 'ldrb' instructions in __aeabi_uread4

Change __aeabi_uread4 from:
    ldrb    r2, [r0, #1]
    ldrb    r1, [r0]
    (...)
to:
    ldrb    r1, [r0]
    ldrb    r2, [r0, #1]
    (...)

This change is a workaround to handle correctly __aeabi_uread4 on ARM
Versatile Express RTSM.
It should not have any major consequence on the other ARM platforms.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@12481 6f19259b-4bc3-4df7-8a09-765794883524