arm: fpu: Convert 'q' registers to 'v' to satisfy clang

Clang doesn't seem to support 'q' register notation in the clobbered
list, and hence throws the following error:

arm/fpu.c:235:3: error: unknown register name 'q0' in asm
                fpu_reg_read(outdata);
                ^
arm/fpu.c:59:10: note: expanded from macro 'fpu_reg_read'
                     : "q0", "q1", "q2", "q3",          \
                       ^
arm/fpu.c:281:3: error: unknown register name 'q0' in asm
                fpu_reg_write(*indata);
                ^
arm/fpu.c:92:10: note: expanded from macro 'fpu_reg_write'
                     : "q0", "q1", "q2", "q3",          \
                       ^
2 errors generated.

Hence, replace 'q' with 'v' registers for the clobbered list.

Fixes: d47d370c ("arm: Add test for FPU/SIMD context save/restore")
Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Signed-off-by: Andrew Jones <andrew.jones@linux.dev>